Ben is born to Kathy and Phil Mitchell in March 1996. Ben becomes ill and is rushed to hospital, where he is diagnosed with meningitis and he is left partially deaf in one ear. As Kathy gives Ben all her affection, Phil turns to alcohol and has an affair with Lorna Cartwright, resulting in the breakdown of their marriage. In 1998, Kathy moves to South Africa and takes Ben with her. He accompanies her on two return visits in 1999 before returning with her to South Africa in early 2000. In 2001, Kathy marries a man named Gavin Sullivan. The same year, Ben briefly returns to stay with Phil who then takes him back to South Africa.
In 2006, the residents hear that Kathy and Gavin have been killed in a car accident, so Ben returns to England to live with his half-brother, Ian Beale. He eventually moves in with Phil, after Phil wins a long custody battle. Ben dislikes Phil's new girlfriend Stella Crawford, who in turn feels that Ben is intruding on their relationship. She abuses Ben physically and psychologically, from burning him with a hot spoon, also attempting to spoil his friendship with Abi Branning when she discovers this, to threatening to kill Phil if Ben tells anyone about her actions. Phil and Stella become engaged. On their wedding day in July 2007, Ben admits that Stella has been abusing him; she commits suicide by jumping from a roof. Phil, a recovering alcoholic, begins drinking again in the aftermath, but resumes a life of sobriety for Ben's sake.
Unbeknown to Phil, Ben develops an interest in dancing. He secretly takes classes, passing a dance exam, and is ultimately able to gain Phil's approval. In March 2010, Phil's daughter Louise comes to stay with the Mitchell family. She steals Ben's diary and fakes an entry which suggests he is gay. In retaliation, Ben burns Louise's hand the same way Stella burnt his. He later locks Louise in a summerhouse for a day in May 2010, then pretends to find her to earn approval from his father. Louise blames Jordan Johnson, an acquaintance of Ben's, but when Phil sees burn marks on Louise's arm, she reveals that Ben is to blame. Phil worries Ben is copying Stella, and punches him when he catches Ben about to burn Louise again. Questioned as to why he hurt Louise, Ben claims that Jordan is bullying him. Phil advises Ben to fight back; soon after, Ben attacks Jordan with a spanner, leaving him with a fractured skull. Phil warns him against admitting to the attack, but Ben confesses and moves in with Ian. After hearing from Crown Court Ben could spend time in juvenile detention, Phil plans to send him to live with his brother Grant abroad, but Ben refuses, thanks to his grandmother, Peggy, making him change his mind, after Phil's girlfriend Shirley Carter overhears Phil discussing the plans to Ben and receives an eight-month sentence as a result. In July 2010, Phil indeed blames Peggy for Ben's sentencing. Ben tells Peggy and Phil he is coping despite being bullied by Cal Childs, and when the Mitchell family discovers this Ben asks them not to visit him.
Ben, is released, and arrives home to discover Jay Brown, the foster child of Phil's relative Billy (Perry Fenwick), has usurped his place in Phil's affections. Ben is jealous of Jay initially but does develop a 'brotherly' relationship with him. Ben vents his anger at those who cross him, punching Phil in the face and pushing Phil's aunt Glenda down a flight of stairs for ruining his homecoming party.
Ben attends a gym and shares his first kiss with boxer, Duncan Willis. When they are seen kissing by shopkeeper Patrick Trueman, Ben throws a brick through Patrick's window and tries to intimidate him into not going public about his homosexuality. Phil observes and misinterprets their altercation, believing Patrick is assaulting Ben. He launches a vendetta against Patrick. After Duncan confronts Ben about his victimisation of Patrick he tells him their kiss didn't mean anything and cuts ties with him, Ben confesses to Phil. Disgusted his son is gay, Phil pushes Ben away, terrified his homosexuality will ruin his reputation. Ben develops feelings for Christian Clarke, who is also gay but engaged to his boyfriend Syed Masood. Ben tries to split them up and attempts to kiss Christian. After being rejected, Ben claims Christian touched him inappropriately as revenge. Phil goes into a violent rampage, hitting Christian with a baseball bat, which prompts Ben to admit the truth. In the wake of this, Phil tries to accept Ben's homosexuality. Billy's granddaughter, Lola Pearce, offers to have sex with Ben to test his sexuality. Ben loses his virginity to Lola in October 2011 and concludes that he is definitely gay. Ben is later concerned to discover Lola is pregnant, however, she denies he is the father.
Ben continues to feel angst towards Phil for rejecting him. He anonymously stalks Phil, terrorising him with evidence about his past crimes, including a newspaper clip of the death of Steve Owen. DCI Jill Marsden, who has been attempting to imprison Phil for over a decade, opens an investigation. She interviews Ben regarding Stella's death in 2007. Ben tells her that Phil forced Stella to jump off a building on threat of being pushed. Phil plans to flee the country before arrest, but is stalled by Ben, who reveals himself as his father's stalker. Phil is charged with Stella's murder and when the Mitchell family discover Ben's involvement in his father's arrest, they disown him. Ben's brother Ian eventually discovers Ben lied to DCI Marsden and informs the police. Phil is released; however, Ben mistakingly believes he has been betrayed by Heather Trott, who also knows he set Phil up. He confronts Heather in fear and desperation, and hits her over the head with a metal picture frame, killing her. Phil returns from prison moments after Heather's murder. Feeling responsible for his son's behaviour, Phil covers up Ben's involvement with Jay's help, who was present when Heather was killed. Shirley, Phil's fiancée, discovers Heather's body, and as she was her best friend, she vows to find the killer. Worried she will discover the truth, Ben convinces Phil to break-up with Shirley and she is thrown out of their home, while Jay is so traumatised by Heather's murder that he moves out of the Mitchells'. Ben and Phil wrestle with guilt and argue regularly, with Phil turning to alcohol. Needing to confide in someone, Ben admits his crime to Ian; the confession contributes to Ian's mental breakdown, and amidst threats from Phil to stay silent, Ian absconds, leaving Phil and Ben searching for him to no avail.
Ben fails to dispose of the photo frame and it is taken by Jean Slater, who is collecting for charity. It is put into the charity shop and later is discovered by Shirley, who realises it is the murder weapon. Tracing it back to the Mitchell house, she confronts Phil, believing him to be the killer, but Ben gives himself away during the argument. Shirley is furious and nearly drowns Ben, but Phil intervenes and convinces Shirley to talk to Ben about why he killed Heather. However, they find Ben gone and he confesses to the police. DCI Marsden does not believe him at first, but he is later arrested for murder. He is charged the next day, and Phil's solicitor Ritchie Scott informs Phil that Ben could face up to 10 years in prison. Phil tries to persuade Ben to change his statement, however, Ben insists that he needs to be punished. Ben refuses to have any contact with anyone until he is released. In October 2012, Ben's murder charge is dropped and Phil is told he will be tried for manslaughter, to which he will plead guilty. Ben then agrees to a visit from Phil, and Phil plans to tell Ben that he is the father of Lola's daughter, Lexi Pearce, though he decides not to. Ben is sentenced to four years imprisonment and discovers he is Lexi's father after a visit from Lola.
After witnessing Ian's grief following his daughter Lucy’s murder, Phil decides to get in touch with Ben; however, Ritchie reveals that Ben was released the previous month. Phil cannot get hold of him, although Jay has seen Ben twice since his release. In September, Ben returns to Walford when he learns that Phil is having an affair with Shirley days before his wedding to Sharon. Ben initially tries to convince his father to reunite with Shirley, but forms a bond with Sharon when she accepts him into the family and acts as Phil's best man at the wedding. After the wedding, Shirley shoots Phil whilst struggling with Sharon. Ronnie asks Ben and Jay to get rid of the gun. Ben meets Johnny Carter and is attracted to him, but when Johnny makes a move Ben reacts badly and says he is not gay and that his interest in men was a phase. He then starts a relationship with Abi in an effort to prove it to Phil and Johnny. When Johnny later leaves the square, he tells Ben not to hide who he truly is. Although Ben continues to deny his attraction to men, he later misinterprets a brotherly moment with Jay and tries to kiss him. Jay later tells Abi, but then lies and says he made it up when he sees how upset she is. Ben eventually confesses to Abi that he's still attracted to men but, desperate to keep him, Abi decides to stay with him, saying their relationship is about more than sex. However, Ben is later seen looking at a gay contacts app on his smartphone.
Ben had instructed Jay to bury Lucy's purse and phone, which has been missing since her death. Denise Fox digs them up in Patrick Trueman's allotment and takes them to Ian, who calls the police before Ben convinces him that he found them on Good Friday in a bag in the Square and had no part in Lucy's murder. Ian lies to the police and protects Ben. When Phil is arrested on suspicion of attempting to kill Ronnie, he puts Ben in charge of his garage. Max Branning starts helping him with deals, only to trick Ben into signing over the garage to him as revenge for the death of his girlfriend Emma Summerhayes, which Max has blamed Phil for, though Phil eventually gets the garage back. Ben then starts a sexual relationship with Paul Coker, whilst maintaining his relationship with Abi. Ben grows frustrated with Abi's controlling behaviour, and she is suspicious, so Ben has sex with her to allay her fears. Phil catches Ben and Paul half-naked together at the car lot, and angrily tells Ben to leave as he broke his trust, both in hiding his homosexuality and being loyal to Abi. Ben ends his relationship with Paul, leaving Paul heartbroken. Paul tries to speak to Ben on numerous occasions, but fails to win Ben's affections over. Ben and Abi decide to find their own home after realising they can no longer stay with Phil after Sharon leaves him. Ben and Paul flirt and arrange to go to the cinema but when Abi finds them and leaves in anger feeling Ben is not taking their plans seriously, Ben follows her, leaving Paul alone. Paul later tells Ben that he loves him and says Ben must decide who really wants and accept who he really is. To give himself more time, Ben books tickets for Abi to visit a friend on holiday, and then tells Paul he loves him back. Jay sees them kissing, and tells Ben to admit to Abi that he loves Paul. When Phil is later sent to hospital and informed that he will be dead within 12 months unless he has a liver transplant, Ben, alongside Sharon and Jay, refuse to visit him, and Sharon has him change the locks on the house so Phil cannot enter when he is discharged.
Ben comes to terms with the fact that his mother Kathy has returned to Walford after faking her own death at the hands of her husband, Gavin. He initially refuses to talks to her, disgusted at the fact that she pretended to be dead for almost ten years, but they reconcile. After Abi returns from her trip to Paris with her friend, she realises that Ben may be having an affair with Paul. Ben plans to break up with Abi, but Abi has been manipulated by Babe Smith (Annette Badland), who tells her to announce she is pregnant so that Ben will not leave her. Abi does this publicly and then plans to get pregnant for real but Ben says they cannot have sex because he thinks he may have caught an STI from a stranger, so Abi resorts to having sex with Lee Carter to try to get pregnant. Ben discovers he has chlamydia, and Abi also has it. She later fakes a miscarriage in an attempt to end her pregnancy lie, but when she upsets Babe, Babe writes Ben a letter revealing the truth. The letter is read by Louise, who has returned, and to keep her from showing it to Ben, Abi allows her to use Phil's credit card. When Ben finds the card, he confronts Abi, but she believes he found the letter so inadvertently reveals she was never pregnant and says that Louise was blackmailing her. Ben takes revenge on Louise in The Queen Vic by putting her head in the toilet. He then seduces Abi and takes her top off, but then drags her into the main bar of the pub, revealing via a karaoke microphone that she invented the pregnancy. Ben then resumes his relationship with Paul with the support of most of his friends and family. Following an agreement with Les and Pam, who make plans to retire and leave Walford, Ben and Paul make arrangements to become the new managers of Coker and Sons. In celebration, they spend a night out together, and are not seen again the next day. Ben's family are alerted by the police that a dead young man whom they believe to be Ben has been found, having been involved in a fight, but upon inspection, the victim is revealed to be Paul. Ben is found by Buster Briggs in SoHo, after managing to make his way back to Walford, albeit with major injuries. He explains that he and Paul were cornered by four large men and chased after coming out of a night club, and were separated when running away. When informed of Paul's death, he lashes out in a violent rage, before breaking down in tears in Kathy and Phil's arms.
Ben later visits the Queen Vic to join his neighbours in a toast to Paul's memory, but Paul's grandmother Pam, blames him for Paul's death and dubs him the worst thing to ever happen to Paul, wishing he had died instead. Ben wishes the same, and later confesses to Johnny that he and Paul were victims of homophobic name-calling, and despite Paul insisting they ignore the culprits, Ben confronted the men, causing the attack, and thus blames himself for Paul's death. Johnny encourages Ben to report this to the police, and Ben recognises one of the attackers outside the police station. Using the man's car registration number, he gets an address and demands a gun from Phil to seek revenge. Phil tricks Ben and does not get a gun, so Ben goes missing. He returns, having failed to find the man. Paul's body is released, and Ben realises Jay has been using cocaine. Jay and Ben decide to help each other move on from their problems, so Ben decides to let the police find the attackers. However, Ben and Jay change their minds, agreeing to take revenge and then leave Walford together. Louise worries that Ben may be about to get into trouble so asks help from Paul's grandfather Les, who tells Ben not to put his family through what he and Pam are going through, as Ben could be killed too. Ben does promise not to track down Paul's killers but when Jay finds an address and says Ben will regret doing nothing, Ben and Jay leave. They return to Walford after Louise calls to the police, but are then kidnapped by the attackers at the Mitchell home. Ben is rescued by his uncle, Grant, and Grant's son Mark Fowler. Jay, who the killers trapped in a van, flees when the police appear. Ben later says a farewell to Jay, who leaves Walford shortly after Paul's funeral and Jay says that they will always be brothers. However, he returns not too long after. Not wanting Phil to die, Ben decides to donate part of his liver to him, but a doctor tells them it will still take time. Despite Ben's discovery that Phil has cut him out of his will, he proceeds with his plan to donate part of his liver, but he is refused by the hospital who are unsatisfied with his answers and emotional responses when interviewed. However, Phil eventually gets a liver transplant.
While Phil and Sharon are on holiday, Ben and Jay move to their own house. On Ben's 21st birthday, Jay throws the pair a housewarming party, where Ben and Johnny have a one-night stand after getting drunk. The next day, they both worry that the other wants a relationship but are relieved to realise they just see each other as friends. After Louise suffers severe burns following a disaster at a school prom, against Sharon's request Ben calls Phil who is Italy recovering from his transplant. Ben signs the paperwork for The Arches when Phil decides to hand it over to him and Sharon is left stunned when he decides to give Jay the car lot land. Kathy insists to Phil that he justifies his reasons to Ben about giving Jay the car lot land that is worth more than The Arches. Ben finds a solicitor's letter of Phil's that mentions Raymond and after confronting Phil, Phil tells Ben that Raymond is his half-brother. Ben is angry with Phil for making him feel second best to Phil and Sharon's other children. Ben learns that Phil offered Jay the car lot out of guilt for killing his apparent biological father, Alan Hall, a victim of the car lot fire that Phil had caused 23 years previously in an insurance scam. After a fight with Jay, they make amends.
Ben meets Luke Browning, the son of James Willmott-Brown, who raped Kathy 30 years previously but is unaware of his identity. They end up kissing and start a sexual relationship, until Ben learns of Luke's family background when Willmott-Brown secretly visits Kathy, and Ben goes to visit Luke with the intention of confronting Willmott-Brown. When Ben meets Willmott-Brown in his office, he confronts him over his actions towards Kathy with a crowbar. Willmott-Brown tells Ben that the sex was consensual and convinces him that he should doubt Kathy's honesty. Ben almost attacks Willmott-Brown but Luke stops him. Feeling that Ben does not trust her, Kathy considers leaving Walford. Ben reluctantly decides to end his relationship with Luke due to the conflicts of interest between Kathy and Willmott-Brown. After a heart to heart with Ben, Kathy decides to remain in Walford and gives Ben and Luke's relationship her blessing. Ben plays a prank on Luke, which backfires when Luke grabs Ben's wrist and threatens him. However, Luke later apologises. Ben accidentally takes Luke's wallet and finds a business card with the words 'Project Dagmar', and confronts Luke about the project as the Dagmar was the bar that Willmott-Brown owned and Kathy worked in when he raped her. Luke lashes out at Ben and physically threatens him. Realising that Ben is a risk to the project being exposed, Luke ends their relationship. Hurt and confused, Ben asks Abi's sister Lauren, who works for Luke's firm, Weyland & Co, about the project but she does not know about it. Luke tries to apologise to Ben by buying him a car but Ben continues to reject Luke and he attacks and brutally beats Ben, so Phil asked his old prison cellmate Aidan Maguire for help and have Luke kidnapped and he is not seen again; it later transpires that Luke was brutally killed by Aidan despite Phil's merely requesting that they scare Luke and not kill him.
Following Luke's death and Willmott-Brown's eventual downfall, Phil joins Aidan in a planned heist and they use The Arches to steal the money. However, the stolen money and jewellery goes missing and it is revealed that Ben realized what was going on and stole it from the funeral home where it was being hidden. He sells the jewellery but keeps one necklace, giving it to Kathy, and then plans to leave the country. He leaves after writing a note for Jay. He is cornered on the ferry by Ian's former wife Mel Owen who warns him to give her the money or he will soon be dead. Ben refuses, saying he only took what he deserved. Mel makes a phone call to someone, telling them that Ben is all theirs. When Ben arrives in France, he is stunned to find the money has been replaced by newspapers. However, he is relieved to discover an envelope full of cash in his pocket. Ben gleefully heads for a new life, unaware that Aidan's former wife Ciara is watching him.
When Phil and Keanu Taylor end up in some trouble in Spain, Phil forges Ben's signature, causing Kathy to call Ben to come home, Ben returns with Lola and their daughter, Lexi, and after seeing the trouble Phil is in, he agrees to help him. However, it is soon revealed Ben is planning to steal Phil's money and leave him broke and he makes Lola follow every instruction, causing him to get annoyed when she ignores him and ends up kissing Jay in The Queen Vic, however it's soon revealed Lola has a fiancé called Ewan.
Ben secretly witnesses Callum "Halfway" Highway attempting to harm himself in the playground. After Ben talks to Halfway about the incident, Halfway then purchases a van from Ben as a gift to his girlfriend Whitney Dean, although he is later pulled over by the police, who inform him that the van is stolen. Halfway confronts Ben and demands a refund; when Halfway attacks him, Ben realises that Halfway is attracted to men, which Halfway denies. He then punches Ben when he mocks him. The two later share a kiss. Halfway continues to deny his attraction men while Ben knows he is living a lie so Halfway proposes to Whitney and she agrees. When Ben learns that Phil has replaced him with Keanu in his will, he is furious. However, he later witnesses Stacey Fowler attack Phil with a wrench, to stop the latter from killing her husband Martin Fowler. He tells them to leave the scene, saying he will sort it out. Martin and Stacey go on the run to avoid prison. Ben incriminates Keanu in the attack which leads to the latter's arrest. Ben later attempts to kill Phil in hospital, but is stopped by Jay. When Phil regains consciousness, Ben tells him that Keanu, who has gone on the run with Louise, who is pregnant with his child, attacked him. However, Phil does not believe him and Stacey's cousin Kat Moon tells him that she attacked him to stop him killing Martin, thereby covering for Stacey. Ben later admits to Phil that Keanu had nothing to do with the attack and that he framed him because he knows about Phil's will. Furious, Phil disowns Ben.
On the day before Halfway and Whitney's wedding, Halfway confesses to Whitney that he kissed Ben, leading her to call off their wedding. Just as Whitney is about to expose Halfway's secret to the packed pub, all of the residents are held hostage by Hunter Owen , who has escaped prison. Ben is shot in the siege, but is revived by Sonia Fowler. The attack on Ben leads to Phil forgiving his son and Ben and Halfway also get together. Martin soon returns to Walford to care for his daughter, Bex Fowler. He pleads with Ben to dispose of the wrench Stacey used to attack Phil, so that she and his kids can return home. However, Ben blackmails Martin into getting involved in criminal jobs for him, saying he will let Stacey come home when he wants to. Ben does dispose of the wrench but further blackmails Martin with footage of him stealing a car. An angry Martin punches Ben and it is then that a past incident of Martin dangling Ben from a railway bridge when he was a child is revisited. Ben says that he is bigger now and will not back down easily. Martin turns to Jack Branning, who has recently rejoined the police for advice, and he gets Ben and his accomplices arrested. Ben is however released on bail. He confronts Martin and the next morning, he tells Martin that he is sorry for what he has put him through and that Stacey is free to return to Walford. However, that evening, Ben and his henchmen kidnap Martin and hang him off the railway bridge, just as Martin did to Ben when he was younger. Ben threatens to have Stacey and their kids killed if she does not stay away and if Martin does not continue working for him. During the Christmas season after finding out, that Keanu Taylor is the father of his stepmother's unborn baby he helps Phil with Martin to kidnap him.