Denise Celeste Fox (previously Johnson, Wicks and Turner) is the sister of Kim Fox, daughter of Emerald Fox, ex-wife of Owen Turner, Kevin Wicks, and Lucas Johnson and mother of Chelsea, Libby and Raymond. She is also the fiancée of Jack Branning.
Moving to Walford, Denise has a fierce encounter with Kevin Wicks; however, an attraction develops, and they begin dating. Denise's former husband, Owen Turner, an alcoholic, tries to reunite with their daughter, Libby Fox and he later kidnaps her. He tries to drown himself and Libby, but she recovers, and Owen is arrested. Denise, who never knew her father but knew he played in a band called "The Five Hectors", thinks that Patrick Trueman maybe her father as he was in the band but a DNA test proves that he is not. The band also consisted of Aubrey Valentine, Cedric Lucas, Dwight and Earl. The identity of Denise's father is never discovered, but Aubrey also eliminates himself.
When Kevin's former wife, Shirley Carter, arrives in Walford, she causes problems for Denise and Kevin. Shirley reveals Kevin's secret that he is not Deano and Carly's biological father. After Shirley tells everyone this, Kevin flees. Upset, Denise threatens to move away but stays when Kevin returns and proposes marriage. Shirley unsuccessfully tries to ruin the wedding, and Denise deals with various problems, including Chelsea and Dean's imprisonment for framing Sean Slater, Kevin's attempts to conceal the crime, and a feud with her boss at the post office, Zainab Masood. Kevin starts selling cars for Phil Mitchell but discovers they are cut-and-shuts; he tries to destroy the vehicles but dies in an accident. Denise and Carly leave Walford after the funeral, seeking the right place to scatter Kevin's ashes.
Denise returns but is angry to discover her daughter Chelsea is using drugs and in contact with her father, former drug addict Lucas Johnson. Denise is initially hostile, but she warms to him when she sees he has changed and they eventually reunite. Denise proposes to Lucas, but he is married to Trina. Trina attempts to seduce Lucas, but he accidentally kills her. Denise helps Jordan come to terms with his mother's death, with them believing it to be an overdose. With Trina dead, Denise and Lucas can marry, though further complications arise when Owen is released from prison. He desperately tries to show Denise that she cannot trust Lucas, but they marry regardless. Lucas kills Owen on their wedding day, and his body is discovered eight months later. Lucas confesses to Denise, claiming self-defence. At first, she agrees to protect him but convinces him to go to the police. However, he instead drives her to a canal. When she refuses to submit to God, he strangles her. He murders a prostitute, Gemma, and identifies her as Denise; her family believe she committed suicide. Lucas keeps Denise prisoner in the house next door, but she escapes after a few weeks, and Lucas is arrested, later sentenced to life imprisonment. Chelsea, needing a fresh start, moves to Spain with Owen's mother, Liz Turner and Libby joins them for a holiday before returning to university. Denise is heartbroken to see her girls leave but is distracted by her sister, Kim Fox, arriving and saying that she has left her boyfriend, Dexter Mulholland, and asks to move in with them.
Kim and Denise later buy the house next door and transform it into a bed and breakfast. Denise talks to Zainab, who helps her move on by destroying memories of Lucas. Denise starts dating Yusef Khan, Zainab's former husband, but ends it after realising he is still in love with Zainab. On Christmas Day 2011, Denise opens a present containing a broken toy car and a USB stick with a recording of Phil talking about his part in Kevin's death. Horrified, Denise calls Phil a murderer and tries to get him arrested but fails to do so.
Yusef starts a fire at the bed and breakfast, damaging it so severely that Denise, Kim and Patrick are forced to move out. The insurance company refuse to pay out as it was arson, so Patrick gives Denise and Kim the Minute Mart, but Zainab gives them Yusef's money so they can rebuild the bed and breakfast. When the B&B opens, Denise is angry that Kim flirts with the customers, leaving all the work to her. They have an argument, and Denise quits but returns on the condition that Kim puts in more effort. When Zainab's brother-in-law, AJ Ahmed arrives in Walford, he attempts to con Denise but fails. The two later have drinks, but AJ leaves. Denise attends Christian Clarke's stag party, where a man gives her unwanted attention. She has sex with Fatboy when he defends her from an overly-persistent interest and allows him to walk her home. The next day, Denise is embarrassed and tells Fatboy it was a mistake. However, it is revealed she has feelings for Fatboy, and after she welcomes him into her home, they have sex again. Denise agrees to pursue a secret relationship with Fatboy. When Fatboy tries to encourage her to make their relationship public, Denise calls it off, telling Fatboy she will treasure the memory of their time together. After a lonely Christmas, Kim and Zainab decide to set up a date for her. However, this fails, and when Kim's boyfriend, Ray Dixon, comforts her, they share a kiss. Ray tells Kim about it but says Denise made the first move, so Kim slaps Denise and says she is dead to her. Denise and Kim reconcile until Ray ends his relationship with Kim. Kim blames Denise, so Denise stays with Ian Beale. When Ray tells Kim the truth, Denise and Kim reconcile, and Denise moves back in with Kim.
When Denise and Ian get locked in the Minute Mart's storage cupboard and share a kiss, it leads to a relationship. This becomes public, thanks to Ian's daughter, Lucy. Denise helps Ian open a restaurant and supports him when Carl White threatens and blackmails him. Denise moves in with Ian and his children, and they are then joined by Cindy Williams, daughter of Ian's dead former wife. Denise begins to feel part of the family and supports Ian when he intends to testify that he saw Max Branning tampering with the brakes of Carl's car. However, Ian fails to do this and Denise is devastated to learn that Ian intended to lie to frame Max on Carl's orders. The return of Ian's former wife, Jane Beale, causes Denise to have doubts about their relationship. She accepts Ian's marriage proposal, and during their engagement party, she shares a kiss with Fatboy. They come to their senses when Cora Cross catches them. Fatboy's girlfriend, Poppy Meadow, learns of the kiss and posts a letter to Ian, before leaving Walford but Lucy reads it and challenges Denise. For the sake of her father's mental health, Lucy agrees to keep it a secret. Denise and Ian drift apart due to his busy lifestyle. After visiting Libby in Oxford, she plans to leave Ian. However, when Lucy is murdered, Denise feels forced to stay and support him. Denise is sidelined by Ian and decides to leave, confiding in Patrick that she feels trapped. However, worried that she will look like a bad person, Denise changes her mind and returns but still feels ostracised. She does not attend Lucy's funeral after seeing Ian and Jane comforting one another. Under advice from Libby, Denise tells Ian she can no longer be with him, but he begs her to stay. Denise agrees to abide when Ian admits he has taken her for granted and encourages her to go with Libby to Spain to celebrate Chelsea's birthday.
On Denise's return, things are much better between her and Ian, and he arranges for them to visit Libby in Oxford for a weekend. As she is about to leave, Patrick tries to stop her but fails and leaves a message, asking her to call him as soon as possible. However, she learns that Patrick has had a stroke and they return to Walford. When he leaves the hospital, he stays with Ian and Denise. Denise knows that Ian had sex with prostitute Rainie Cross on the night Lucy died. Feeling betrayed, Denise locks herself in the Minute Mart. On returning home, she discovers that Cindy has returned and that Ian has delivered her newborn daughter, Beth. She tells Ian that she forgives him but leaves him the next day, taking Patrick back to live in his own house, declaring that Ian isn't the man she loved. Going into Patrick's house, Denise is devastated to find that the house has been broken into. Denise struggles to care for Patrick alone, despite support from Shabnam Masood. She considers that Denise has been stealing alcohol from the shop but does not report it if Denise returns the value. Patrick is devastated to learn that he may lose his allotment, so Denise goes there, intending to maintain it, only to dig up Lucy's phone and purse. Although hesitant, she returns them to the Beales.
On New Year's Eve, a pregnant Kim surprises Denise and accuses Ian of ruining Denise's life. The next day, Kim finds bruises on Patrick's arms and realises Denise had beaten him and confronts her. At the pub, Denise gets drunk, and after hearing of Emma Summerhayes's death, drunkenly slurs that Lucy's killer would be jailed if Emma had done her job correctly. In anger of Denise's disrespectfulness, Ian says that despite what Kim said, Denise has been ruining her own life. On arriving home, she tells Kim she cannot be Patrick's carer anymore. After an argument with Denise in The Queen Victoria public house, Kim goes into labour and gives birth to a daughter named Pearl. Although she disowns Denise, they eventually reconcile the next day. After Pearl's christening, she tells Denise that her husband doesn't exist and she made him up because of fear of being alone. However, Kim's confessions to Shirley, Kat Moon, Linda Carter and Patrick reveal that her husband does exist, but she left him when she found out that he was a criminal. Eventually, when her husband Vincent Hubbard tracks her down in Walford, Kim works up the courage to tell Denise the truth about him and explains her experience when she went to tell him she was pregnant. Denise and Patrick soon become wary of Vincent's intentions.
Denise is visited by the police, saying someone in their custody has given her address as theirs. Eventually, she realises that it is Jordan. She discovers that Jordan stole from Chelsea and Libby advises Denise to stay away from him. Denise visits Lucas in prison, and he tells her that he thinks about her, asking her to find Jordan. Despite her family begging her not to, Denise sends Jordan a message online. He does not reply but visits and tells her to leave him alone. However, when Kim hits Jordan, he allows Denise to clean the wound. The rest of the family poorly receives Jordan, but Denise defends him after he pushes her in frustration, he leaves when Patrick says he is just like Lucas. The police visit Denise and tell her that Jordan was attacked by a gang but discharged himself from the hospital. She tracks him down and learns that Jordan's girlfriend died from a drug overdose. Denise brings Jordan and his son, JJ Johnson, home and although Patrick comes around to the idea, Kim believes it will bring Lucas back into Denise's life. Denise revisits Lucas, and he wants Jordan to visit too. He does, and Denise agrees to help Lucas get a job in the prison kitchens, but Lucas asks Jordan to help him in his plan for him to escape from prison.
When Jordan tells Denise, she refuses to help and alerts Libby to call the police, after which Jordan reveals to them the truth about Lucas' plan before he is arrested. Denise vows to look after JJ until Jordan is released, but Patrick secretly calls social services. Social worker Hilary Taylor tells Denise that JJ's mother, Amelle, is alive. Amelle visits Denise and JJ, but he refuses to come out from under the table. Denise learns JJ is called Jamie and she talks to him; he says Jordan told him that Amelle left because she found him "hard work" and he is only hiding because he is scared of putting Amelle off him. Denise persuades him to see his mother, and when Hilary talks about increased contact, Denise decides JJ should live with Amelle. Denise finds out Libby is pregnant and attempts to stop a termination but fails; distressed, Denise turns to drink and has a one-night stand with an equally drunk Phil, but Phil has no memory of this.
Denise befriends Carmel Kazemi and has a brief fling with her son, Kush Kazemi. Denise ends it, saying she does not want to ruin her friendship with Carmel. When Denise faints, she researches her symptoms and initially fears that she has cancer but discovers that she is pregnant. Kush learns about Denise's pregnancy and believing he is the father, goes with Denise to her appointment. Denise knows she is 18-19 weeks pregnant, meaning Phil is the father. Denise tells her family but refuses to name the father. Denise tells Carmel that she has decided to have the baby and put it up for adoption. Kim finds out about Denise's plans and tries to talk her out of it whilst Patrick agrees to support her. Kim tells Denise that she and Vincent will adopt her baby, but Denise declines their offer. Shirley suspects that her former boyfriend, Buster Briggs, is the father but Denise admits that Phil is the father. Unbeknownst to Denise and Shirley, Phil's wife, Sharon Mitchell, overhears this. Denise is later taken to the hospital to be induced. Kim and their mother, Emerald Fox, also go to the hospital. Kim and Emerald are angry when they learn that Denise is putting her son up for adoption, but Denise refuses to change her mind and says an emotional farewell to her son alone. Sharon tells Phil the truth about his son, and he goes to the hospital, demanding to see him but then agrees to the adoption. Libby, Emerald and Carmel come to accept Denise's decision, but Kim is against it, calling her selfish and saying Denise is dead to her. Denise is injured in a bus crash but rejects Kim when she tries to support her.
After a check-up at the hospital, Denise admits to Mick Carter that Kim was right and that she should never have given up her son for adoption, though he reassures her that it is the best decision she has made for him. Denise soon realises that Kim still sees her as a mother figure since Emerald abandoned them as children and thinks that if Denise can give up her son, then she can leave Kim, so Denise tells to consider herself abandoned. Denise later goes to Emerald's farewell party where Emerald criticises Kim's parenting; Denise stands up for Kim and Kim admits that she is thankful for her sister, to which Emerald replies that they are not sisters and that Denise was brought to her as a baby. Emerald then leaves and Kim and Denise hug. Denise confronts schoolboy Keegan Baker after he vandalises the garden in the square. After continuously insulting Denise, she hits him in the face. Using witnesses to his advantage, Keegan reports Denise to the police, and she is consequently fined £250.
Denise later learns that her son's potential adoptive parents have named him Raymond and she signs the adoption forms. While she is adamant that she will not change her mind after that, she continues to struggle with her decision and angrily tears up a newly arrived letter from Raymond's adoptive parents without reading it. Kim then wrongly believes that Ian is Raymond's biological father and confronts him, causing Denise to break down and admit to her that Phil is the father, shocking Kim, and she begs Kim not to tell anyone. With Kim's help, Denise finds the letter from Raymond's parents in the recycling bin, informing her that he is happy with them, which comforts and reassures her. Denise and Kush start a relationship, but when Denise talks to a reporter, criticising the community and the Minute Mart, she quits her job after they decide to send her on a course. Denise struggles financially and is unable to buy food, taking food from bins. She ends her relationship with Kush because she does not want to admit her problems. Carmel later confronts her over this, but Denise slaps her when she remarks Raymond, ending their friendship. Denise eventually claims for Universal Credit but is stunned that she will not receive money for ten weeks as she left her job voluntarily, but is given a referral to a food bank. Denise goes to the food bank when she sees Cora, who works there. Cora persuades Denise to get some food and explains that when she first used the food bank, she was abusive, but it saved her life. Denise gives her food to the children of a young mother, Candice, who has no voucher. On the day of her final exam, Denise faints, but she is delighted later in the year when she passes her GCSE exam with high marks. Kush and Denise decide to try dating again, but when Kush asks Denise to move in with him, she declines, feeling that things are moving too fast for them. When Kush suffers a heart attack shortly afterwards, Denise regrets rejecting him and spontaneously proposes to him in the hospital; he accepts. Denise discovers that Kim is pregnant, but Kim suffers a miscarriage and continues to lie that about her "pregnancy". Kim later cracks up and tells Denise and Carmel that she is not pregnant and is lying and they support her. For her birthday, Kim asks Denise to do a DNA test, and she agrees. When the results come, Denise finds a card for her by Kim, which says they are not sisters, but Kim explains she has not seen the results and got cards for both outcomes. Denise and Kim agree not to find out, but Kim gives in and fools Denise that the results say they are not sisters, but is delighted when Kim states they are.