Mukasa joined KCCA FC from Express FC in 1971 as a goalkeeper . He kept five clean sheets in the campaign and featured in 16 games. Mukasa retired from football in 1978 and turned to coaching, handling clubs like SC Villa, Express FC, Coffee United SC and Nsambya FC among other football clubs.[4]
Mukasa won one league title with SC Villa in 1982, He also won the Uganda Cup twice in 1983 with SC Villa and in 1985 with Express FC.
On the 13th of August 1983, SC Villa played against Millers FC in a match league at Nakivubo stadium, it is at that game that George Mukasa was ordered off the pitch for misbehaving after one of his players (Rogers Nsubuga) suffered a minor injury shortly before halftime, after several solicitations by referee Dick Nsubuga, all fell on deaf ears.[5] This forced Dick Nsubuga to ask George Mukasa to vacate the touchline before the second half begun. This match eventually ended 1-1.[5]
George Mukasa's acts annoyed SC Villa officials including the club President at the time (Patrick Kawooya),this led to his one-month suspension and before he could return, FUFA also gave him a one-year ban for the same incident against the Millers. later the ban was lifted allowing George Mukasa to perform his duties yet again.
On September 14, 1984,he returned to Villa Park but the club had already fallen from its glory and KCCA FC had been declared the league winners.
George Mukasa coached The Cranes in 1984, guiding the team to the Cecafa Cup semifinal, he also played for the national team from 1971 to1976.[6] Mukasa coached the Uganda Cranes between 1984 -1985.[1]
George Mukasa introduced the Kawowo style of play at the National team between 1984 and 1985. However much this was entertaining, it yielded no results for the Uganda Cranes as they lost to Malawi at the CECAF semi finals games that were held at the Cranes home grounds,this led to his dismissal in 1985.[7]