Following the death of his serial killer stepfather Richard Hillman (Brian Capron) and the departure of his biological father, Martin (Sean Wilson), the character took a darker turn in 2006, becoming increasingly rebellious and antagonistic, deprived of a male role model.

As a result, he has notably feuded with Phil Nail (Clive Russell), Bill Webster (Peter Armitage), Charlie Stubbs (Bill Ward), Gary Windass (Mikey North), Jason Grimshaw (Ryan Thomas), Callum Logan (Sean Ward) and Clayton Hibbs (Callum Harrison), as well as his sister, Sarah Platt (Tina O'Brien), and mother, Gail Platt (Helen Worth).

He develops romantic feelings for Maria Sutherland (Samia Longchambon), but is annoyed she is enjoying an affair with Charlie Stubbs (Bill Ward).

David smashes various vehicles and windows on the Street, attacks Ken Barlow (William Roache) and hits a policewoman.

He dates Amber Kalirai (Nikki Patel) in an attempt to make Tina jealous, which has the desired effect and they get back together.

In November 2008, David feuds with the Windass family when they refuse to pay for work that Tina's father Joe McIntyre (Reece Dinsdale) has carried out.

He then enlists Gary to commit robbery, which goes wrong when Gail's father Ted Page (Michael Byrne), interrupts them, calls the police and has a heart attack.

David discovers that Joe is addicted to prescription medication and agrees to supply him with drugs as long as he tries to break Tina and Jason up.

In February 2010, Joe drowns in a boating accident while on his honeymoon in the Lake District, but the police presume that he has been murdered and arrest Gail.

David returns from a holiday in Tenerife and announces his engagement to "Candy", aka Kylie Turner (Paula Lane).

Following their reconciliation, and a holiday to Barbados to visit Becky, Max's behaviour at home and at school gets worse and is diagnosed with ADHD in August 2014, and Kylie becomes addicted to his medication.

In a quest to get to the source of Max's ADHD, she travels to her old haunt, a pub called The Dog & Gun in Wythenshawe, where she grew up.

The pair continued to have secret meetings for weeks where Kylie gets hooked on amphetamine and Callum demands to see Max.

[2] David is initially the main suspect, but they frame the recently deceased Tony Stewart (Terence Maynard), Jason's father, another of Callum's enemies, who happens to be dead.

Their plans are ruined when Clayton Hibbs (Callum Harrison) stabs Kylie in the street and she dies in David's arms.

After he makes a suicide video, Gail, Nick, and Sarah see it and lock David inside the cellar of the Bistro until the trial is finished.

After tricking Gail into thinking that he has committed suicide, David escapes the Bistro, gets into his car that is doused in petrol and drives off.

In 2017, he begins a relationship with an older woman, Shona Ramsey (Julia Goulding), who he later discovers is Clayton's estranged mother.

Following the rape, David starts lashing out at everyone, worrying Shona, Gail, Martin, Sarah, Gary, Bethany and Audrey as well as many other residents.

He later starts a relationship with apprentice hairdresser Emma Brooker (Alexandra Mardell) who is only a year older than his niece Bethany.

On the day of his trial for attacking Gary, he runs off while his solicitor Imran Habeeb (Charlie de Melo) is distracted.

While doing community service for beating up Gary, he and another man make homophobic jibes towards gay vicar Billy Mayhew (Daniel Brocklebank).

David later manages to ring Shona via mobile phone to tell her what happened, she asks whether he stabbed Josh or not but doesn't answer.

Later, his solicitor Imran Habeeb visits David in the hospital, notifying him that Josh was found guilty of raping him and other people and that he received a sentence of 15 years.

[3] In January 2018, it was confirmed that Sean Wilson would be returning to Coronation Street after a thirteen-year absence as David's father Martin as part of the rape storyline.

His behaviour included sending greetings cards to his family supposedly from his murderous ex-stepfather Richard Hillman (Brian Capron), setting fire to his GCSE exam paper in front of dozens of his fellow students and driving himself into the canal (mirroring Hillman's attempt to murder his entire family in 2003) in an effort to ruin Sarah and Jason Grimshaw's wedding day.

[8] In July 2018, Shepherd was longlisted for "Best Actor" and "Best Partnership", alongside Julia Goulding who plays Shona Ramsey, at the Inside Soap Awards.

[9] For his portrayal of David, Shepherd was nominated for Best Soap Actor (Male) at the 2018 Digital Spy Reader Awards; he came in third place with 9.5% of the total vote.

[10] In 2019, Shepherd received a National Television Awards nomination in the Serial Drama Performance category for his portrayal of David.

[12][13] Fearing real-life imitation of the scene in which David was tortured by Charlie Stubbs, many formal complaints were filed by viewers with the Government's Office of Communications.