[1] Carl is the ex-boyfriend of Kirsty Branning (Kierston Wareing), and his storylines include tracking down cash owed to him by Derek Branning (Jamie Foreman) – which Ian Beale (Adam Woodyatt) has used to open a restaurant; trying to win Kirsty back; a relationship with Roxy Mitchell (Rita Simons); his feuds with Roxy's cousin Phil (Steve McFadden) and Derek's brother Max (Jake Wood); blackmailing Ian for money; and developing a conflict with Roxy's sister Ronnie (Samantha Womack) that ultimately results in his downfall.

Carl arrives at Bianca Butcher's (Patsy Palmer) house, after she telephones him thinking his number belonged to her father David Wicks (Michael French).

He learns that Derek is dead, and claims to know his daughter Alice Branning (Jasmyn Banks), so Bianca gives him her address.

[2] The next day, Carl sees his ex-girlfriend, Kirsty Branning (Kierston Wareing), who says she is now married and pregnant, and he has no reason to stay.

[7] Phil is hospitalised and Carl frames Max for cutting the brakes[8] after forcing Ian to become a false witness, promising to cancel the debt.

[9] Max ends his relationship with Kirsty[10] under Carl's instructions, who has threatened to harm his daughter Lauren Branning (Jacqueline Jossa).

[11] Carl attempts to take over Phil's businesses while he is in hospital,[12] and after Shirley Carter (Linda Henry) challenges him, she mysteriously disappears.

Max declines and leaves, so Phil prepares to kill him instead until Carl implies that he caused harm to Shirley and knows where she is.

[16] He leads Phil to a block of run-down flats where Shirley is staying with her sister, Tina Carter (Luisa Bradshaw-White).

[20] She confronts Carl, who is violent towards her and a final threat leads to her hitting him over the head with a champagne bottle; he falls unconscious.

[21] She ties him up in Phil's garage and the next day tells him to leave Walford and never return, but he ignores her and attempts to rape her, kissing her forcefully.

"[23] Executive producer Lorraine Newman said: "It's wonderful to have Daniel Coonan joining us in Walford to play Carl White.

[25] Heat reported that Carl's introduction was part of a "rescue plan" to increase ratings for EastEnders, especially with the announced departures of popular characters Tanya Branning (Jo Joyner), Jack Branning (Scott Maslen) and Michael Moon (Steve John Shepherd), saying "with ever-dwindling ratings and an unusually bare trophy cabinet, producers have been forced to plan some major shake-ups in an attempt to revive the ailing drama with new characters, returning familiar faces and exciting storylines.

"[24] Inside Soap called Carl "nasty" and "evil", and said that he fills the "super-villain" role last taken by Derek, hoping that he would "shake the Square to its foundations.

[25] He also said Carl presents "different fronts to different people"[25] and opined that there is "a bit of nice in him", but he likes to dominate, make money and have influence, and would not be good until he achieves that.

He is entrepreneurial, pragmatic and ingenious, and could have been a successful businessman if he did not choose a life of crime, though it was the only way he knew to get women, cars and money.

"[41] Carl is brought to Walford by Bianca Butcher (Patsy Palmer) after she finds his telephone number in her uncle Derek's belongings.

"[31] However, he thought that Kirsty may not want to reunite with Carl because "he's not the type of guy who's just going to change overnight" and he is probably not "the knight in shining armour" he thinks he is.

[37] Coonan went on to say that Carl would treat Kirsty "like a goddess" but would probably have a problem with her independence, and he would want to provide for her, being "old-fashioned and a bit misguided", and they would have a "fiery" relationship because they are both "strong-willed".

[37] Kierston Wareing, who plays Kirsty, opined that her character is more suited to Carl than to Max, and hoped they could be a "manipulative, power couple".

[42] In July 2013, Carl's mother Nora White is introduced for a single episode, played by Lynn Farleigh, when he and Kirsty visit her in a nursing home.

Inside Soap said that Nora is "pure, unbridled evil" and her introduction might show why Carl is a menace, giving viewers a "glimpse into [his] twisted upbringing".

[31] Coonan said that Carl causes the crash because he wants to depose Phil as "top boy" in Albert Square, saying it is "such an insane thing to do.

[37] On filming the crash, Coonan explained that he was inside the car when the glass was detonated, and he suffered cuts on his leg and hand.

[48] Danny Walker from the Daily Mirror said, "if you try and kill a Mitchell and blame Max Branning for cutting the brakes, it will have repercussions.

"[49] Coonan revealed that in the run-up to his departure, Carl becomes a "bit of a lone wolf" after giving up trying to win Kirsty back, and said he has no friends because he has threatened everyone.

[28] Coonan shares scenes with actresses Samantha Womack, who plays Ronnie Mitchell, and Rita Simons, who plays Roxy Mitchell, but the actor explained that both characters realise that Carl is "a bit too dark to get involved with" and he is "probably going a bit mad because he can't get Kirsty back".

"[52] On 24 September 2013, it was announced that Carl, along with three other characters—Kirsty Branning (Kierston Wareing), Poppy Meadow (Rachel Bright) and AJ Ahmed (Phaldut Sharma)—had been axed from the series by the new executive producer Dominic Treadwell-Collins.

[55] Gary Gillatt from Inside Soap wrote of Carl's arrival, "Walford's new super-villain shows big promise.

"[58] Filipa Jodelka from The Guardian said, "Carl is an EastEnders speciality, a new character shoehorned in with a backstory that's not so much shadowy as completely obscured.