Kelly reached the last 16 in the welterweight division in Rio before being beaten by the eventual champion, Daniyar Yeleussinov.
Kelly reached the last 16 in the welterweight division in Rio before being beaten by the eventual champion, Daniyar Yeleussinov of Kazakhstan.
He will be coached by the well-regarded Adam Booth, with the 22-year-old set to make his professional debut as a welterweight on the undercard of Ricky Burns's world light-welterweight unification title fight against Julius Indongo in Glasgow on April 15.
Kelly joins fellow Olympians Lawrence Okolie, Joe Cordina and Ireland's Katie Taylor as a Matchroom boxer, while Britain's Nicola Adams signed with experienced promoter Frank Warren.
"I want to get fans across the whole of Britain and beyond to want to watch me and come to my fights," said Kelly. "I think they'll see flash and flair, and there will be KOs (knockouts) too. I can mix it up and fight to different game plans.
"I drew the eventual champion in the Olympics and I really think that there were just two or three punch differences in each of the rounds, it could've been a different story but that's how it goes. I've moved on from that."