Simmons formed the rock band Wicked Lester in the early 1970s with Stanley Eisen, who later became Paul Stanley in KISS. Wicked Lester recorded an album together, but as of 2002, it has never been released. Eventually, two other musicians joined the band, Peter Criscoula and Paul Frehley - who would become Peter Criss and Ace Frehley when the band changed its name to KISS in the early 1970s. KISS released their first self-titled debut album in February of 1974.
Simmons is also a movie producer and actor who has appereared in a number of movies including Runaway. He also created the animated television series called My Dad The Rock Star, by the Canadian animation company Nelvana about a mild mannered son of a Gene Simmons like rock star who wanted to live a normal life, but his wealthy and eccentric father make it that near impossible.