Boy George was born to Jeremiah and Dinah O'Dowd (nee Glynn), who were originally from Thurles, County Tipperary, Ireland. He lived with his family on the Middle Park Estate at Joan Crescent London SE9. He attended Eltham Green School in Eltham. He is one of six children. His siblings are Richard, Kevin, David, Gerald, and Siobhan.
He was a follower of the New Romantic movement which was popular in Britain in the early 1980s. George frequently lived at the infamous Warren Street Squat in Central London. George and his friend Marilyn were regulars at The Blitz, a trendy London nightclub run by Steve Strange of the group Visage. George and Marilyn also worked at the nightclub as cloakroom attendants

When Boy George was with Culture Club, much was made of his androgynous appearance, and there was speculation about his sexuality. When asked in interviews, George gave various answers. He gave a famous, oft-quoted response to an interviewer that he preferred "a nice cup of tea" to sex. In Take It Like a Man, George told his side of his secret relationships with punk rock singer Kirk Brandon and Culture Club drummer Jon Moss. He stated many of the songs he wrote for Culture Club were directed at Moss. However, one of Culture Club's biggest hits "Do You Really Want to Hurt Me" was about Brandon. Moss acknowledged that he had a sexual and romantic relationship with George, but Brandon denies he ever had a relationship with George.
In 2006, in an episodic documentary directed by Simon George titled The Madness of Boy George, George declared on camera he was "militantly gay". In a 2008 documentary Living with Boy George, he talks about his first realisation he was gay, and when he first told his parents. He discloses that he understands why men fall in love with one another as well as with women.