The following are characters who first appeared in the BBC soap opera EastEnders during 2012 listed by order of first appearance. New characters were introduced by Bryan Kirkwood, executive producer. He stepped down from the role in April. His last episode was on 13 July 2012. From 16 July, characters were introduced by his successor, Lorraine Newman.

The first character to be introduced was the undertaker, Les Coker (Roger Sloman). The first regular character to be announced was Ray Dixon (Chucky Venn), the biological father of Morgan Butcher (Devon Higgs), followed by Alice Branning (Jasmyn Banks), the daughter of Derek Branning (Jamie Foreman) and, Alice's brother, Joey (David Witts). June 2012 also saw the first birth of the year: Janine Butcher (Charlie Brooks) and Michael Moon's (Steve John Shepherd) daughter, Scarlett. July saw the arrival of Masood Ahmed's (Nitin Ganatra) brother, AJ Ahmed (Phaldut Sharma). July also saw the second birth of the year: Lola Pearce's (Danielle Harold) daughter Lexi, Newman's first introduction. After the announcement that Sharon Rickman (Letitia Dean) was returning, her son Dennis Rickman Jnr (Harry Hickles), was introduced, along with guest character, Sharon's fiancé John Hewland (Jesse Birdsall). Danny Pennant (Gary Lucy) arrived in September, as part of a love triangle storyline involving Syed Masood (Marc Elliott) and Christian Clarke (John Partridge). Ava Hartman (Clare Perkins), the long-lost daughter of Cora Cross (Ann Mitchell) was introduced in November and Kirsty Branning (Kierston Wareing), Max's (Jake Wood) secret wife, made her first appearance on Christmas Day. December also saw the arrival of Zainab Khan's (Nina Wadia) family friend, Ayesha Rana (Shivani Ghai).

Les Coker, played by Roger Sloman, first appeared on 9 January 2012. He subsequently appeared in five episodes in 2012, before returning for an episode in 2014. Les was reintroduced as a regular character in April 2014 and continued to appear until 14 October 2016 when the character was axed from the show.

Les first appears when he visits Carol Jackson (Lindsey Coulson) and David Wicks (Michael French) to arrange Pat Evans' (Pam St Clement) funeral. He tells them he used to know Pat when he was an apprentice, implying he was her client when she was a prostitute, and offers a discount on the funeral. He says that he arranged funerals for many of the other local residents, including David's father Pete Beale (Peter Dean), Pat's husband Roy Evans (Tony Caunter), Ethel Skinner (Gretchen Franklin), Pat's former sister-in-law Pauline Fowler (Wendy Richard) and Archie Mitchell (Larry Lamb). He returns to meet Jean Slater (Gillian Wright) to finalise arrangements for the funeral of her daughter Stacey Branning (Lacey Turner). Jean is distressed to hear that Stacey has died, but Mo Harris (Laila Morse) reveals she has just spoken to Stacey on the phone, meaning Stacey is alive. Les apologises profoundly before leaving. Les is seen by Sasha Dixon (Rebecca Sanneh) doing business with Anthony Moon (Matt Lapinskas) and it turns out that when someone dies, Les offers to empty their house and sells the goods to Anthony for his business. Sasha and her employer, Cora Cross (Ann Mitchell), then ask Les to offer every other house to them for the charity shop. He attends a wake for a former Walford resident at The Queen Victoria public house, where Kim Fox (Tameka Empson) pretends to know the deceased, and talks to Les, successfully gaining Sasha a work experience placement with Les's firm. He attends the wake of a man previously known by Patrick Trueman (Rudolph Walker) and is annoyed when Cora turns up, as he has agreements with her and Anthony. Les later appears when Sasha starts her first day of work experience.

Les appears again to arrange Nick Cotton's (John Altman) funeral, although it is later revealed to be a scam in which Les is in on. Les moves his funeral business, Coker & Sons Funeral Parlour, to Turpin Road following the relocation of Pam's flower stall to Bridge Street Market. When walking home one night, Fatboy (Ricky Norwood) notices Les being handed money by Dot Branning's (June Brown) grandson, Charlie Cotton (Declan Bennett). Fatboy tries to tell Dot what Les and Charlie are up to, but is unsuccessful. In July, Les hires Billy Mitchell (Perry Fenwick) at the undertakers, however he is disappointed when Billy doesn't turn up for work on his first day. Pam is upset when Les insults Emma Summerhayes (Anna Acton) while drunk, fearful it will reveal a big secret they have been keeping; that she euthanised their dying son, Lawrie. Billy eventually establishes a good working relationship with Les and a friendship as they spend Christmas together. Billy discovers the business is deeply in debt and forces Les to tell Pam this. They vow no more secrets, but after Les meets with his "other woman", Claudette Hubbard (Ellen Thomas) and gives her an expensive necklace. Claudette and Pam are revealed to be old friends, as Claudette is a foster mother and Pam used to help children in care. Les holidays in Gran Canaria with Claudette, although Pam sees it as a coincidence when she learns from Claudette's foster daughter Donna Yates (Lisa Hammond) that they are both there at the same time.

Les arranges a party for the centenary of Coker & Sons, and Pam gets upset at the thought that their grandson, Paul (Jonny Labey), will not attend. The same day, Paul returns but is cold towards Les. He reveals he is aware of his long running affair with Claudette and that was why he went to work abroad in the first place, not because of Pam's decision to euthanise his father as they previously believed. Paul threatens to expose the affair to Pam so Les tries to end things with Claudette, but Claudette tells Les that it will not be that easy. Claudette's son Vincent Hubbard (Richard Blackwood) then becomes aware of the relationship between her and Les, and Paul tells Pam about it. Pam then finds Les's tie at Claudette's house, and when Les and Claudette give conflicting explanations, Pam leaves to stay with her sister. Les becomes very distraught at her departure, and Claudette urges him to tell Pam the truth, just as Pam returns and walks in on them together. Shortly after Claudette leaves the house, Pam urges Les to end the affair or their marriage is over. Two months later, Les visits Claudette for comfort after Pam refuses to speak to him on Lawrie's birthday. He later calls Claudette, telling her he cannot stop thinking about her, and makes an excuse to Pam to go and be with Claudette again. He is then caught in his underwear in Claudette's house by Donna, who concludes they are having an affair, and despite Les and Claudette denying it, Donna tells Pam what she saw. Pam then goes to Claudette's house and sets about destroying gifts from Les until Claudette says the presents are not hers, and Pam should ask Les about Christine. When Pam asks Les, he reveals that Christine is his secret feminine alter ego, where he dresses up in women's clothes and has done so since he was seven years old, but after they married he did not need Christine until Lawrie died, when the alter-ego became a grief outlet for him, and Claudette has been supporting this secret. Pam is horrified at him having lied to, and tells Les he disgusts her. However, Pam agrees to "meet" Christine. Les, as Christine, explains that this is how he can cope with things, as Christine is more open than Les, and he is still the same person. Pam apparently begins to accept this, but when Paul interrupts, Pam says she cannot accept it, so packs a bag and leaves, while Paul comforts Les. Paul manages to convince Pam to return home to talk to Les, but when she gets hesitant again, Les moves out to give Pam some time to think, and he moves in with Billy. Pam and Les have dinner together but she still cannot get the image of him dressed as Christine out of her mind, soLes burns all of Christine's clothes and photos and Pam agrees to take things one day at a time, but Babe Smith (Annette Badland) is watching and finds and pockets a surviving photo of Les dressed as Christine. Shortly after, Paul encourages Les to remind Pam of the man she first fell in love with and she agrees to his moving back in as long as they sleep in separate beds.

A few months later, Les spurns Babe, so she sends Les an anonymous email, blackmailing him over his crossdressing. When Pam notices money has been paid from their account, Les admits he has been blackmailed. The blackmailing continues regularly, and Pam starts to suspect Babe, and eventually they discover the truth. Les confides in Claudette and says he misses Christine, so she gives him some of her clothes and makeup that she still has. Stressed, Les dresses up again but is caught by Paul. Paul refuses to destroy Christine's things for Les, saying Les should not suffer for who he is. When Pam finds Les dressed as Christine, she chastises him and he suffers a heart attack. Billy sees him as he enters the ambulance. Billy calls Les a "pervert" to Pam, so she fires him from the funeral parlour. Pam then tells Les they should retire away from London and Les agrees; when Paul and his boyfriend Ben Mitchell (Harry Reid) find out, they decide they should take over the running of the funeral parlour. Paul's mother, Jenny Rawlinson (Amy Marston), arrives looking for him, but he only assumes she is the blackmailer and orders her away. Pam and Les vow to tell Paul who she is, but Paul is killed in a homophobic attack. Pam struggles to cope, refusing to talk to Les about Paul, so he considers dressing as Christine; he explains why he cross-dresses to Billy and gives him his job back. Les then decides to be strong for Pam so tells Claudette he will no longer be Christine, but the blackmailing continues, with Pam refusing to go to the police, but she tells Claudette that Babe is the blackmailer. After four months of blackmail, Claudette reveals this to Babe's family, and Babe, who has just been attacked by Abi Branning (Lorna Fitzgerald) and come close to death, tells Claudette that she now sees how bad she has been and regrets everything, so it will stop. Les and Pam later attend a court hearing for Paul's killers. Les calls one of them, Simon Atmore (Tom Palmer), a liar after he denies having anything to do with Paul's death. When they arrive home, Pam tells him he needs to be Christine again. Les later suffers a small heart attack after talking to Linda Carter (Kellie Bright) who tries to comfort him and he eventually dresses up as Christine. Les then asks Pam if she would consider leaving Walford together for a fresh start after the trial is over which she agrees. Les and Pam are delighted when Babe returns all of their money. However, they decide to leave and Les appoints Billy as the manager of Coker and Sons. Pam packs a box of Christine's wig and clothes suggesting she has accepted her. After saying an emotional farewell to his friends and after giving Billy his funeral hat, Les departs with Pam for a new life in Worthing.

Having been originally introduced as the funeral director who arranged Pat Evans' (Pam St Clement) funeral, Sloman appeared in one episode on 9 January 2012 as a guest character. He then appeared in five episodes between June and July 2012. Les was reintroduced for one episode on 25 March 2014 when he arranges Nick Cotton's (John Altman) funeral. Following this, Sloman was reintroduced as a regular cast member with Les' wife, Pam (Lin Blakley) being introduced also. Executive producer Dominic Treadwell-Collins said "Les and Pam are part of our plans to rejuvenate the show's older generation. It's already so exciting to watch the chemistry between Roger and Lin on set, playing characters who have been together for so long, they know each other inside out. Or so they think." Les and Pam arrived on 14 April 2014 when they relocated their funeral business to Turpin Road.