His interest in bodybuilding started by the age of 8 and after moving to England for studying law and from 1967, he began to compete, winning the title Mr Southeast Britain the same year.
[2] He retired from competitive bodybuilding afterwards and had a brief role in Dušan Makavejev's film Sweet Movie.
Callender started his professional wrestling career in 1974, making his ring debut against Killer Tim Brooks in Montreal.
[5] He was the winner of the 1979 IFBB Pro Universe, edging out his compatriot Albert Beckles.
[2] After his fifth Olympia in 1984, he had a hiatus of three years in his native country and after placing seventh at the IFBB Grand Prix in Essen, he retired in 1987.