Hung joined the China Drama Academy, a Peking Opera School in Hong Kong, in 1961. He was enrolled for a period of seven years, beginning at the age of 9, after his grandparents heard about the school from their friends. The opera school was run by Master Yu Jim Yuen and as was customary for all students, Hung adopted the given name of his sifu as his family name whilst attending. Going by the name Yuen Lung, Hung became the foremost member of the Seven Little Fortunes (七小福) performing group, and would establish a friendly rivalry with one of the younger students, Yuen Lo. Yuen Lo would go on to become international superstar Jackie Chan. At the age of 14, Hung was selected by a Teacher who had connections to the Hong Kong film industry to perform Stunts on a movie. This brief foray into the industry piqued his interest in film and he took particular interest in the operation of film cameras. As the eldest of the troupe, Hung would give his opera school brothers pocket money from his earnings, endearing him greatly to his young friends. Shortly before leaving the Academy at the age of 16, Hung suffered an injury that left him bedridden for an extended period, during which time his weight ballooned. After finding work in the film industry as a stuntman, he was given a nickname after a well-known Chinese cartoon character, Sam-mo (三毛; Three Hairs).