Born in Cuba of mixed Cuban and Jamaican descent, Aitken and his family settled in Jamaica in 1938. After an early career working for the Jamaican Tourist Board singing calypso songs for visitors arriving at Kingston Harbour, he became a popular nightclub entertainer. His first recordings in the late 1950s were calypso tunes such as "Sweet Chariot", "Aitken's Boogie", and "Baba Kill Me Goat". Progressing to a pre-ska shuffle, Aitken's 1958 single "Little Sheila" / "Boogie in My Bones" was one of the first records produced by future Island Records founder Chris Blackwell.
Aitken moved to London, England in 1960 and recorded both in the UK and Jamaica throughout the 1960s. This cemented his position as one of ska's leading artists and earned him the nicknames The Godfather of Ska and Boss Skinhead. He gained a loyal following not only among the West Indian community, but also among mods, skinheads and other ska fans. He had hit records in the United Kingdom and other countries in the 1950s through to the 1970s on labels such as Blue Beat, Pama, Trojan, Rio, Dr. Bird, Nu-Beat, Ska-Beat, and Dice. Some of his singles featured B-sides credited to his brother, guitarist Bobby Aitken. Aitken also recorded a few talk-over/deejay tracks under the guise of 'King Horror', such as "Loch Ness Monster", "Dracula, Prince of Darkness", and "The Hole". Aitken settled in Leicester with his wife in 1971. Aitken's career took in mento/calypso, R&B, ska, rock steady, and reggae, and in the 1990s he even turned his talents to dancehall. He performed occasional concerts almost until his death from a heart attack in 2005. After a long campaign, a blue plaque in his honour was put up at his Leicester home in 2007.