Beckles was born in Barbados but emigrated to London. In the mid 1960s, he won several British regional titles before winning the 1969 and 1970 NABBA Mr. Britain titles. In 1971, Beckles joined the IFBB, earning the overall at the IFBB "Mr. Universe."
Beckles was one of the most active participants in bodybuilding history, having been in over 100 contests. In 1982 he won the Night of Champions competition in New York.
Beckles’ record-setting 13 forays into the IFBB Mr. Olympia have yielded six placings among the top five, including coming second to Lee Haney in 1985.
In 1991, at the age of 61 years old, he won the Niagara Falls Pro Invitational.
In 1991, at the age of 61 years old, he won the Niagara Falls Pro Invitational.