Billy was born to Jessie Grant and Evan Fletcher. Evan died when Billy was young and Jessie went on to remarry, resulting in the birth of Billy's half-brother, Ellis Chapman. Much to Jessie's horror, Billy fell in with the wrong crowd and was desperate to impress his new friends. During a night out following their exams, a man named Evan Norwood was viciously beaten and left for dead by Billy and his friends. Under Joint Enterprise laws, Billy was sentenced to three years imprisonment for the assault along with his friends, Luke Dockley, Nathan Delfield, and Freddie Hart. Jessie was convinced of her son's innocence, although Ellis, whose relationship with Billy had fallen apart as Billy refused to stop his friends from bullying Ellis, was just as convinced of his brother's guilt.
In September 2018, Jessie revealed Billy would be granted early release from prison later in the year. In November 2018, Billy was hospitalised after a fight with another inmate, who was also hospitalised.
2018-2019: Arrival in Emmerdale and troubles with the lawOn Christmas Day 2018, Billy turned up at Jessie's wedding to Marlon Dingle, having been released from prison. Jessie was elated to see her son and proclaimed the day was "perfect". The joy quickly faded away when Marlon's first cousin once removed, Aaron Dingle, attacked Billy. Aaron had previously mentioned to his husband Robert Sugden that Billy was part of the prison gang that made his short prison sentence almost two years ago a living hell. Ellis also wasn't happy with his brother's arrival as he unlike his mother didn't believe Billy's prison time was due to bad luck and falling in with the bad type of people but rather his own doing.
In January 2019, Billy got a job for Jai Sharma at the sweet factory as a delivery driver. Later, Ellis' girlfriend Victoria Barton, who wants the brothers to make up lures Billy to the scrapyard then locks him and Ellis in the port-a-kabin and instructs them to sort things out. A claustrophobic Billy begins to panic although Ellis manages to calm him down. After calming down the brothers begin to talk and Billy insists that he wants to start again and make things right. When Victoria unlocks the cabin door, Billy orders her not to ever lock him in again then storms out. Although their relationship remained rocky they started building up a relationship and grew closer. In February, Billy starts flirting with Tracy Metcalfe. At a party, Ellis attempts to put Tracy off Billy but it backfires, resulting in Tracy kissing Billy.In late March, Tracy convinces Billy to go to an interview for an apprenticeship at a garage, and as Billy and Tracy head off, Ellis asks them to pick up Billy's young step-sister, April. Later, Billy and Tracy watch April play in a park when two police officers approach Billy and explain a concerned parent has reported he was acting suspiciously. Tracy believes Billy has been targeted because he's black, but Billy tells her to let it go. April asks Billy if he's going back to prison which the woman who reported him takes as confirmation that Billy was dodgy. Tracy turns around and storms towards her, accusing her of being racist. While she protests that she's not, Billy holds Tracy back as she and the woman engage in a slanging match, resulting in Tracy being arrested. Later, Billy is annoyed at Tracy and explains that people like him have had it the same all their lives and he didn't need her acting the saviour. Billy also asks April to keep quiet about what happened in the park as it'll upset Marlon and Jessie, however, they find out from Ellis, upsetting Billy who doesn't want to make it a big deal. Ellis approaches Billy outside the pub to apologise but Billy ends up pinning him against the wall. Tracy runs over and questions what Billy thinks he's doing and furiously walks off with Ellis. The next day, Billy apologises to Tracy for yesterday but she states she is over him.
On 12th April 2019, Billy is approached by an old acquaintance, Max Garrick, who asks Billy to work for him as a getaway driver during a robbery. Billy initially refuses but later agrees as he needs money. However, Ellis finds out and tries to stop Billy from heading off to meet Max by setting off the fire alarm in the factory, making him miss the robbery. Afterwards, Ellis warns Billy that if he goes through with the robbery, they are through but Billy states that it's too late anyway and tells his brother that thanks to him, he's made himself an enemy. The following day a threatening Max turns up at Tall Trees Cottage wanting what Billy cost him by pulling out of the warehouse robbery. When Billy doesn't give him what he wants Max punches Billy so Billy goes for him and they fight. Ellis returns home and pulls Max off Billy, then Billy orders Max to do one but Max vows he'll be back which leaves Billy fearing Max will never leave him alone. Max goes on to threaten Billy and his family in order to pressure him to do another job for him.
On 25th April, as Ellis goes on a group night out with some of the villagers, Billy fears for his brother's safety when Max sends him a picture of Ellis at the club. The following day, the family visits Ellis in hospital after he was stabbed. Jessie is convinced Max is to blame but Billy is reluctant towards telling the police. On 7th May, Billy reveals the true story behind the night at the club to Ellis. Whilst looking for Ellis, Billy got pinned up against a wall by two men whom Billy assumed to be Max's minions, however, the men reveal they're actually Kaiden and Tyler, the brothers of Riley - the man Billy viciously attacked, resulting in him being sent to prison. A fight ensued and Billy admitted to attacking Riley and declared that he wishes he would've finished him off as he was racist, drug-dealing scum who pushed his friend Ben to kill himself at eighteen because he was so scared of Riley. Billy made a run for it and managed to lose them. However, Billy calls Ellis to apologise and as the brothers were talking, Billy heard muffling sounds and realised Ellis was in trouble. As a frantic Billy searched for Ellis, he ran into Kaiden and Tyler who told him they were even now. Billy discovered Ellis lying unconscious with blood pouring from his side after being stabbed using Billy's knife. As instructed by the 999 operators, Billy put pressure on Ellis' stab wound, but he soon left when he saw blue lights of the ambulance approaching. Following the revelation, Ellis and Billy decide to put this behind them as they got rid the knife together.In June 2019, Billy was forced to agree to participate in a job with Max, however, Max and his gang soon realise Billy has set them up and tipped off the police. On 25th June, Max went to Billy's house and held Jessie, Marlon and April hostage as revenge. Billy arrived at the house which was surrounded by the police and despite their warnings, Billy sneaks in via the back door. He manages to get April out to safety and a struggle ensues between him and Max. Billy continues to beat an incapacitated Max until Marlon pulls him off him. Whilst a shell-shocked Jessie hugs Billy, a battered and bloody Max reaches for the gun and pulls the trigger, ending up shooting Jessie. She is taken to hospital where she luckily recovered, however, Marlon blamed Billy for Jessie's injuries and was far from pleased by his presence at the hospital. Billy explains to Jessie that everything that's happened all comes back to what he did to Riley. He explains drug dealer Riley was the reason his best friend, Ben, is dead, and when he saw Riley, he couldn't control himself. Jessie can't believe it but soon decides to forgive her son as she recalls how the last time she saw her father, they argued and she doesn't want her son to have those regrets.
2019-: Jessie's departure and DI Malone
In August 2019, Ellis and Billy go into business together, wanting to start a personal training business but runs into problems when Jessie can't afford to invest. However, Ellis is enthusiastic when an investment company shows interest in their personal training business and organises a meeting. Billy skips out on the meeting but he and Jessie get a shock when the man at Ellis' meeting turns up at Tall Trees Cottage, and reveals himself to be Ellis' dad, Al Chapman. Billy remains sceptical towards Al and insists he only wants to buy people. However, much to Billy's dismay Al states he's staying around and Ellis soon decides to give him a chance.
In September 2019, Billy is furious to learn Al has slept with Jessie and is devastated when that leads her and Marlon's marriage to fall apart. Jessie moves to Dubai after getting a job offer there and Billy and Ellis start considering moving, thinking it would be complicated to stay at Marlon's. However, after some persuasion from Marlon and April, who they have both come to see as a little sister, they decide to stay and turn on Al, both taking Marlon's side. Al and Billy continued to clash but they tried to put aside their differences for Ellis' sake.
In March 2020, Billy got himself involved with bent copper DI Malone alongside Dawn's father Will Taylor and his boss Cain Dingle. They tried to get out of it but when they didn't do what he asked Malone got Billy arrested based on made-up charges with the promise that it would all go away as long as they all did what he wanted. The men eventually agreed to do one last job for him in order to keep Billy out of prison and keep Malone from hurting their families. When the day finally came, Billy and Cain were surprised when Malone told them Will wouldn't be coming as he wasn't coping well and sent them out to retrieve drugs alone. However, at the same time, Will found out Malone was trying to set Cain and Billy up and desperately called Dawn who saved their skin.
"'Cause you're either the hard man, or the punchbag. And that's the only option for a young black man. And that kind of thing, it destroys you."