Southend United Kelman scored 61 goals at youth level for
Southend United in the 2017–18 season. He made his professional debut for Southend in a
League One match against
Plymouth Argyle on January 12, 2019. He also scored his first professional goal in that match, finding the net from inside his own half in the second minute of stoppage time at the end despite Southend United losing 3–2. In his second season playing for Southend's first team, Kelman played in 18 games and was Southend's leading scorer in League One with five goals. Kelman appeared 26 times for QPR's first team, mainly coming on from the bench. He did however score a penalty in a 5–3 penalty shootout win over
Leyton Orient in the first round of the
EFL Cup. Upon returning from his highly successful second loan spell at Leyton Orient Kelman informed QPR CEO Christian Nourry he did not want to extend his contract at the club leading to the club deciding to listen to offers for him
Loans to Gillingham On August 31, 2021, Kelman joined
Gillingham on a season-long loan. He returned however to his parent club in November due to frustrations about a lack of playing time. On January 14, 2022, with previous manager
Steve Evans having left the club, Kelman returned to Gillingham for the remainder of the season.
Leyton Orient (first loan) On July 25, 2022, Kelman signed for League Two club
Leyton Orient on a season-long loan deal.
Wigan Athletic (loan) On January 31, 2024, Kelman signed a contract extension with Queens Park Rangers, subsequently joining League One club
Wigan Athletic on loan for the remainder of the season.
Leyton Orient (second loan) . On June 29, 2024, Kelman signed for League One club
Leyton Orient on a season-long loan deal. Having helped the club reach the play-offs, winning the League One Golden Boot with twenty-one goals, Kelman was named
EFL League One Player of the Month for April 2025.
Charlton Athletic On July 27, 2025,
Charlton Athletic made an offer which Queens Park Rangers accepted, leading to Kelman signing a four-year contract with the Addicks. ==International career==