He was introduced by executive producer Kate Oates in episode 5893, broadcast on 29 March 2019, as the patriarch of the Atkins family, which included Gray, his wife Chantelle (Jessica Plummer), and children Mia (Mahalia Malcolm) and Mackenzie (Isaac Lemonius).

In September 2020, EastEnders announced that the storyline would end with Gray killing Chantelle to reflect the impact of the COVID-19 pandemic on domestic violence, which included a sharp increase in spousal murders.

He murdered Tina Carter (Luisa Bradshaw-White) and Kush Kazemi (Davood Ghadami) before entering a second marriage to Chelsea Fox (Zaraah Abrahams), with the two having a son together, Jordan Atkins.

In episode 6649, broadcast 10 March 2022, Gray's departure was depicted as his arrest after his murders were finally uncovered, a downfall Smith considered "a long time coming".

Smith was subjected to online harassment on social media from people who struggled to differentiate him from his character, which he noted saw a peak during Gray and Chantelle's domestic abuse storyline.

Gray arrives in Albert Square with his wife, Chantelle (Jessica Plummer), and their two children, Mia (Mahalia Malcolm) and Mackenzie (Isaac Lemonius), to start anew together.

Chantelle is fatally impaled from the impact and dies from blood loss after Gray, despite his fault, chooses to watch her succumb to her injuries rather than provide help before he stages the scene to make her death appear accidental.

Gray comes close to killing himself and his kids by attempting to fill his flat with gas fumes with his lighter but is stopped by fellow neighbour, Shirley Carter (Linda Henry).

He momentarily offers to represent Tina in court after she is accused of assaulting Ian Beale (Adam Woodyatt) at The Queen Victoria public house.

[2] Smith said he was "delighted" to join EastEnders, as he had been a fan of the soap for a long time, adding that he was "looking forward to seeing what Albert Square [had] in store for Gray".

[8] The show worked with charities such as Refuge and Women's Aid, which specialise in helping victims of domestic abuse, to portray the storyline in an accurate and sensitive manner.

[8][10] Sandra Horley, chief executive of Refuge, explained: "The more we all understand domestic abuse [and the more we can spot the signs], the more women, like Chantelle, will be able to seek help", adding that the organisation commended EastEnders for highlighting this "insidious issue".

[10] He added that: "to the unaware eye Gray appears to be a loving husband and a committed father; but his charm is a front for the power and control he exerts over Chantelle – an experience all too common to thousands of women up and down the country today".

[10] The actor hoped that by tackling the subject, the show could raise awareness of "the importance of changing societal values so that both women and men's rights to live free from abuse, invasion, disempowerment and intimidation are respected".

[13] Smith believed Gray's abusive behaviour was a reflection of his desire for "power and control", adding that "the minute something slips off-kilter, [...] he panics", afraid of losing everything he has.

[16] Gray later grew violent again with Chantelle, to the extent that he accidentally broke her arm, and, after discovering that she didn't tell him about the miscarriage, raped her in hope that she would conceive another child.

[24] As a result, around one month later in September 2020, Oates and fellow boss, Jon Sen, came to the decision to have the domestic abuse storyline conclude with Gray killing Chantelle following an escalation of his violence towards her during quarantine.

[26] Sen commented that the storyline was important to air and that the ending was planned to be tragic from the beginning "with the intention of embedding the stark reality of domestic abuse at the heart of the Atkins family".

He added that: "being able to shed light on the realities of what goes on behind closed doors has never been more crucial given the harrowing statistics as a result of the current pandemic and hopefully Chantelle’s story will encourage people to speak out to someone they trust and get the support that they need".

[26] Smith felt it was important for the story to end tragically, echoing hopes that the storyline's conclusion would help give people the courage to speak out "before it's too late".

[24][25] Following criticism that the story may discourage victims of domestic abuse from leaving, Teresa Parker, head of communications at Women's Aid, explained that it is a realistic conclusion supported by research and wanted it to create "important conversations".

[28] Smith appeared on the ITV talk show Loose Women and was asked why EastEnders chose to announce Chantelle's death before the scene aired, to which he responded that the reason was because it may have triggered some viewers, especially those who had experienced domestic abuse before.

[33][34] Gray convinced Tina's family that she fled Walford to escape legal charges for the attack on Ian Beale (Adam Woodyatt), and disposed of her corpse in an unknown location.

[66] She did disclose that the revelation would come as a big shock to Whitney, as she previously believed that Phil (Steve McFadden) and Ben Mitchell (Max Bowden) were responsible for Kush's death.

[104][105] Smith and Plummer were nominated for "Best Soap Partnership" at the 2020 I Talk Telly Awards, but lost to Ian Bartholomew and Shelley King (Geoff Metcalfe and Yasmeen Nazir, Coronation Street).

[109] The scene where Gray kills Chantelle was nominated for "Must-See Moment" at the 2021 British Academy Television Awards, but lost to Diversity's Britain's Got Talent performance based on the events of 2020.

[121] Chantelle's death scene was labelled a "bullseye" by Inside Soap, with the magazine writing that it was not only "explosive, brutal, and horrific", but that Gray had left people contemplating the "true meaning of evil".

[128] The decision was also criticised by Kitson's colleague, Claire Lindsay, who labelled it "a quick gasp which served to further undermine a powerful story and give an unnecessarily gruesome ending to one of the few generally amiable guys in the [soap] genre".

She continued, commenting that "the dispatching of Kush to give Gray a few more months of shelf life is just one in a long line of botched up death stories [in soap operas]".

[134] The amount of time it took for Kheerat and Whitney to report Gray to the authorities was criticised by audiences, a sentiment echoed by McGarty, who admitted that "maybe they should have gone to the police sooner, but then it wouldn't be EastEnders".