Jason was the first openly homosexual man to appear in Emmerdale. Carlton told Laura-Jayne Tyler of Inside Soap "I played the first gay man in Emmerdale - and there weren't many of them in the soaps back then. I didn't realise how important it was at the time, but it really hit home when I started getting letters from people saying thank you." Tyler stated that Jason became popular with viewers during his time in the soap due to his affair with Bernice Blackstock's (Samantha Giles) boyfriend, Gavin Ferris (Robert Beck).
Jason first appeared in 1999, on his cousin Paddy's doorstep after his parents had thrown him out after he had told them he was gay. Paddy had told Jason to keep this a secret as Paddy's then-in-laws, the Dingles, wouldn't take it well. Jason later had an affair with Gavin Ferris, who had previously been engaged to Bernice Blackstock. Jason helps deliver Latisha Daggert's baby, and when he and Latisha realised her baby was a boy, she named him Kirk Daggert as a thank you to Jason. Jason left for Portugal on 31 January 2002, but he came back briefly in December 2002 to offer Latisha and her family jobs. Latisha, her mother Cynthia and Kirk, moved to Portugal with Jason.