Ronnie is known to have bad luck with her children, with her daughter, Danielle, dying as well as her son, James, having a cot death, and herself suffering a miscarriage in 2009. Her only child that is still living is Matthew, who lives with his father after Ronnie's death.
Ronnie and Roxy visit Walford for their cousin Phil's wedding to Stella Crawford, to see their aunt Peggy Mitchell and stay to run The Queen Victoria while she is on holiday.
Ronnie goes into partnership with businessman Jack Branning (Scott Maslen), purchasing a local nightclub together, and begin an on-off relationship. During a period of separation, Roxy becomes pregnant by Jack after a one-night stand. Ronnie, unaware of who the father is, offers to support her sister and they briefly return to Ibiza. After an argument, Roxy visits their father in Weymouth, to Ronnie's horror. She is relieved when Roxy returns to the Square but horrified when Peggy announces that she and Archie are engaged. Roxy gives birth to a daughter, Amy Mitchell, named after the daughter Ronnie lost. Ronnie is hurt when she learns of Amy's paternity but eventually forgives them both.
Ronnie has a tumultuous relationship with employee, Danielle Jones (Lauren Crace). On Archie and Peggy's wedding day, Danielle tells Ronnie that she is her daughter. Ronnie does not believe her because Archie told her her daughter was dead, and throws her out. She later realizes that Danielle was telling the truth and tries to apologize to Danielle but she is hit by a car and dies in Ronnie's arms. Danielle's adoptive father comes to London to get her and takes Danielle's remains back to Telford and bans Ronnie from the funeral. Despite this, Ronnie goes to Telford regardless and Stacey Slater convinces Andy Jones to talk to Ronnie about Danielle. Grieving for the daughter she wasn't allowed to raise, Ronnie becomes obsessed with having a baby. She tries tricking Jack into getting her pregnant and rekindles her romance with Joel, Danielle's birth father, until she learns that he has had a vasectomy so Ronnie ends their relationship. She gets pregnant by Owen Turner (Lee Ross), but miscarries when Archie pushes her into the bar during an argument. Archie is later murdered and Ronnie is arrested as a suspect but released without charge. When Roxy accuses Ronnie of murdering their father, Ronnie reveals that Archie raped Stacey Slater (Lacey Turner), and did the same to her. Stacey's husband Bradley Branning (Charlie Clements) is posthumously assumed guilty of the murder after falling from the roof of the Queen Vic while trying to evade police arrest.
On Ronnie's birthday, Jack proposes and she accepts. When the issue of Archie raping Ronnie arises again, Peggy refuses to believe it but later learns that Ronnie is telling the truth and that Glenda knew but did not stop it. Ronnie learns of this and disowns her, though they later reconcile. When Ronnie learns that Stacey killed Archie, she allows her to leave the country after the police are called, feeling that Stacey has suffered enough.
Ronnie's cousin Sam Mitchell (Danniella Westbrook) has a son, Richard Mitchell. Jack is revealed to be Richard's father, following a brief relationship. Ronnie is also pregnant but they agree that Richard will live with Jack and Ronnie when Sam feels unable to cope with parenthood but, having given a child up for adoption, Ronnie can see that Sam is having doubts. Consequently Ronnie gives her money so she and Richard can leave Walford together. She and Jack marry and prepare for the birth of their child. Ronnie bonds with Kat Moon (Jessie Wallace) over being abused as children and have given their first child up for adoption.Baby Swap|With Jack abroad on business, Ronnie gives birth to a boy called James Branning but he dies of sudden infant death syndrome within days of being born and as Ronnie seeks help, she swaps her child with Kat's newborn son, Tommy Moon. Ronnie soon regrets her actions but it is too late as James has been found and Jack has returned and met Tommy, thinking he is his son. Ronnie struggles to bond with Tommy and refuses to let anyone see him. She is refused permission to attend James's funeral but goes anyway. At the wake, she gives Tommy to Kat but her intention is misunderstood and leads Jack to think she needs psychiatric help. Ronnie discovers that Michael Moon (Steve John Shepherd) is Tommy's birth father and tries to sabotage his relationships with Roxy and Jack so he will leave Walford but Michael convinces Jack that Ronnie is obsessed with him. Unable to explain her actions, Ronnie agrees that she needs professional help and visits a counsellor but leaves before the session and lies to Jack about it. Glenda realises that Ronnie is not attending counselling but is forced to leave Walford. Ronnie briefly goes missing, and after Jack brings her home, her behaviour becomes increasingly erratic. After visiting the hospital where James was born, she finally admits the truth and returns Tommy to Kat.
Questioned at the police station about her mental health, Ronnie admits that she has been having flashbacks since Danielle's death. She is remanded in custody and asks Jack to move on. Roxy convinces Ronnie to apply for bail, which she is granted. Jack forgives her and they resume their relationship. Michael attempts to frame Ronnie for kidnapping Tommy so she will get a custodial sentence. She is sentenced to three years and as she is being taken away, Kat tells her that she forgives her. Ronnie then says goodbye to Roxy, telling her that she was the one looking after her for the last few years. Ronnie sits alone in her cell, holding Danielle's locket, having finally found peace. Jack tries to visit Ronnie but she refuses to see him and in December 2011, she files for divorce. In 2012, the divorce is finalised.
In September 2013, Roxy, Jack and Kat are notified that Ronnie is being released from prison. Roxy wants to meet her but Alfie Moon (Shane Richie), Tommy's stepfather, who Roxy is now engaged to, protests. Kat goes instead and brings Ronnie back to Albert Square. Alfie insists Ronnie keep her distance, when he finds the sisters reminiscing with Tommy, nearby. As a result, Roxy cuts ties with Ronnie and spends time healing things with Alfie, away from the Square. During this time, Ronnie reconciles with Jack, but when it comes to going public, Jack cannot do it and decides to leave Walford. Ronnie's cousin, Phil Mitchell (Steve McFadden), puts Ronnie in charge of his businesses, while he recovers from a car accident. She makes an enemy in Carl White (Daniel Coonan), when he attempts to muscle in on the businesses. When Roxy returns to the Square, she and Ronnie make peace but Ronnie becomes suspicious about Alfie's feelings for Kat. She is proved right when he leaves Roxy just after their wedding ceremony. Roxy then starts dating Carl and when Ronnie fails to pull her back together, she convinces Phil to sell The Queen Vic, the pub that Kat and Alfie lease from him, to force them out of Walford. However, Roxy continues to see Carl and Ronnie decides to take Roxy and Amy to Ibiza. When Carl learns about this, he threatens to rape Ronnie and, when he attacks her, she kills him in self-defence. She and Roxy then leave for Ibiza, after disposing of the body and only Phil is aware of her actions.
When they return, several months later, Ronnie reveals that she has bought the local gym, which she renames "Basher's". She learns that Sharon Rickman (Letitia Dean) and Shirley Carter (Linda Henry) know what happened to Carl and tells Roxy the truth, who accepts Ronnie's explanation of the incident. Carl's family put pressure on Ronnie as they ask about Carl's whereabouts. When they realise that Ronnie has something to do with his disappearance, Carl's brother, Adam White (Ben Wigzell), snatches Lola Pearce's (Danielle Harold) daughter, Lexi Pearce, while she is in the care of Ronnie and Roxy. Ronnie and Phil track her down and Ronnie hires Alexs Shirovs (Kristian Kiehling) to beat Adam up. The following month, Ronnie accidentally runs Lola over, in the same spot where Danielle died. Ronnie is full of remorse for her actions and Lola soon forgives her, realising that Ronnie never intended to harm her.
Ronnie has a brief relationship with Dot's grandson, Charlie Cotton Jr (Declan Bennett) after telling him about Danielle's death. Ronnie and Roxy buy 27 Albert Square, after deciding that Phil's house is too crowded, but after revealing that she is pregnant to Phil, Ronnie decides to leave. Ronnie returns several months later, as requested by Peggy to try to stop Phil and Sharon's wedding, revealing that she is five months pregnant with Charlie's baby. She moves back in with Roxy. Dot, disappointed about the idea of her great-grandchild being born out of wedlock, persuades Charlie to propose to Ronnie. She admits that she has killed a man and, in return, he admits that he is not a police officer and has been lying to Dot about Nick's death. Nick returns to Walford and reveals himself to Dot. Ronnie tells Charlie that she wants him gone. She threatens Nick, saying that he doesn't know what she's capable of. She asks Phil to give her the money stolen from her and Roxy so she can get rid of Nick, but he refuses. Ronnie steals all the money in his safe. On their wedding day, Phil finds out about the money, and agrees to kill Nick. He overhears this and angrily cuts the brakes on Ronnie's car. She goes into labour during the wedding reception, and Roxy and Charlie rush her to hospital, but crash the car in the square due to the cut brakes. Ronnie is rushed to hospital in a critical condition, where her son Matthew is delivered by an emergency Caesarean section. She is revived at the last minute, but is placed in a coma for several months, before she is finally woken up. After two further months of rehabilitation, Vincent Hubbard (Richard Blackwood), a man who it is revealed Ronnie was seeing in the autumn of 2013, visits her. Roxy breaks down and admits that, while she was in her coma, she slept with Charlie in their upsets. Ronnie forgives her and tries to move forward, but has doubts about her marriage.
On returning home, Ronnie sets up cameras to spy on Charlie and Roxy, paranoid they might sleep together again. Roxy starts a secret relationship, and Ronnie is furious when she finds out she is seeing Dean Wicks (Matt Di Angelo), who raped Linda Carter (Kellie Bright). Dean finds Ronnie's hidden cameras, and Roxy moves out, feeling violated. Ronnie kisses and sleeps with Vincent again, despite them both being married. Ronnie admits she doesn't love Charlie, and ends their marriage. Charlie and Roxy come up with a plan to flee to France with Matthew, but Roxy secretly tells Ronnie and they plan to double cross Charlie and get him arrested. However, events backfire and Ronnie nearly loses Matthew, though Charlie returns to Walford soon after. Ronnie asks Vincent to help her get rid of Charlie, and he disappears, with Roxy finding his discarded wallet. Ronnie admits to Vincent's wife Kim Fox-Hubbard (Tameka Empson), that they were having an affair but ended it. When Dean becomes increasingly controlling over Roxy, Ronnie asks Linda's help to get rid of him. Linda turns her away, but her partner, Dean's brother Mick Carter (Danny Dyer), later visits Ronnie and agrees to help her. However, he cannot go through with the plan at the last minute. Dean and Roxy decide to move away, upsetting Ronnie, so she gets Billy Mitchell (Perry Fenwick) to rob his salon. However, Dean realises she was behind it, so proposes to Roxy in front of Ronnie. She tries to pay him off to leave, but he realises she is recording their conversation, so plays it to Roxy at their engagement party. They argue, and Ronnie smashes up the Albert bar, before she tells Billy she is going to kill Dean. He warns Mick, and eventually Dean's parents Buster Briggs (Karl Howman) and Shirley, who arrive after Ronnie has given him a drink full of crushed up drugs. She reveals it was only a plan to scare him, but it is enough to make Roxy confess to Dean that Ronnie is a murderer. Dean convinces Roxy to go to the police. She later asks Honey Mitchell (Emma Barton) to move in with her. Ronnie is seemingly arrested during a family dinner with the Mitchells. However, Ronnie realises they aren't police, and they drop her off in a wasteland, only for her to be picked up by Vincent. He tells her the police are going to charge her for Carl's murder, and she needs to get out of the country. She decides to confess to the police, but Vincent admits that he is a police informant, and Ronnie argrees to leave. However, Fatboy (Ricky Norwood) gives her a file he found in Vincent's safe, revealing he is working to take down the Mitchells. Vincent tries to blackmail her into framing Phil for drug trafficking, using a confession of her admitting to killing Carl. Phil, who has returned to drinking, disowns Ronnie, but she still protects him when Vincent plants a gun on him and calls the police. After, Ronnie destroys the copies of her confession and keeps the gun, threatening to kill Vincent if he threatens her again.
Ronnie learns that Vincent is seeking revenge on Phil because Phil's father Eric killed Vincent's father Henry. The tensions between the Mitchells and the Hubbards increase when Phil snatches Vincent's infant daughter, Pearl Fox-Hubbard. Ronnie helps negotiate what she thinks is a truce between the two men, but Fatboy informs her that Vincent is still planning to kill Phil. She organises for men to take Vincent, lock him in the boot of his car and have it crushed. She is distracted when Jack returns to spend Christmas with Amy. When Ronnie sees Vincent and he has no knowledge of the car, she realises someone else is in the car boot, but finds it has already been taken to be crushed. After Ronnie tells Vincent what she had planned, he goes to the scrapyard and finds Fatboy's phone and necklace and some blood in the boot. He decides not to tell Ronnie this, and lies that the boot was empty. Ronnie then rekindles her relationship with Jack. She learns from Mick of Dean's attempted rape of Roxy, and Roxy plans to move to Portugal. Glenda returns and tells Ronnie to stop Roxy from leaving but they are unsuccessful when Roxy says Ronnie has controlled her and she needs to be alone for now. Ronnie reevaluates her life and, believing that this is the reason why her and Jack are no longer together, asks Jack to leave with Amy as she too needs to be alone for a while. Before leaving, Glenda tells Ronnie that Eric could not have killed Henry and that Vincent's mother, Claudette Hubbard (Ellen Thomas), must be lying to him. Ronnie then tells Claudette to either remain civil towards the Mitchells or she will tell Vincent the truth about what happened to Henry.
Ronnie and Jack married on Sunday 1st January 2017. Later that day, at their after party Roxy gave Max Branning (Jack's brother) her key to her bedroom and Max put some of her drugs inside her drink. He did this to get revenge on Phil Mitchell, who bribed the jury to give him innocence and Max being guilty for the murder of Lucy Beale. Whilst Honey Mitchell was looking after Jack and Ronnie's children, she asked Jack to read them a bedtime story. This lead to a drunken Roxy and Ronnie's death as Roxy jumped into a swimming pool whilst drugged, which lead to her banging her head on the side of the pool and drowning. Once Ronnie realised what had happened, she jumped into the pool in her wedding dress and drowned while trying to save Roxy due to getting entangled in her wedding dress. The pair then die and lie motionless in the water as Jack reads the story of Cinderella to Ronnie's children.
Ronnie's final appearance was on 19 January 2017 when she was seen in her coffin, witnessed by Jack.
1. Carl White (January 2014) - Bludgeoned with a car boot lid by Ronnie.
2. Arthur "Fatboy" Chubb (December 2015) - Ronnie hired henchmen to kidnap Vincent Hubbard and put him in the boot of a car which would later be crushed, however Fatboy was mistaken for Vincent and killed in the car instead
- 2009 duff duff count- Ronnie Mitchell had the most duff duff (cliffhangers) of the year.