Simmons was inspired to become a rock star when he saw a televised performance by the Beatles. He put his first band together, The Missing Links, with classmates while attending Joseph Pulitzer Middle School.

As a teenager, Simmons formed several bands including The Long Island Sounds and Bullfrog Bheer. He met fellow KISS co-founder Paul Stanley in 1970 and they formed their first attempt at a band, called Wicked Lester. Though the band developed a prominent following in the New York rock scene, Simmons worked several odd jobs to make a living, including as a 6th grade teacher in Spanish Harlem and an assistant to an editor at Vogue Magazine.

In the winter of 1972, with a desire to create the ultimate rock band, Simmons and Stanley formed KISS with original band members Peter Criss and Paul “Ace” Frehley. Inspired by his love of comic books and horror films, Simmons conceived the face paint concept. The addition of elaborate costumes, frenetic stage performance and
extravagant effects catapulted KISS to international stardom and a coveted position as one of the most recognized rock and roll bands in the world.

KISS was inducted into the Rock & Roll Hall of Fame in 2014 and in 1999 received a star on the Hollywood Walk of Fame.

In December of 2023, KISS held its last two concerts at Madison Square Garden in New York.

Simmons continues to hit the stage with his Gene Simmons’ Band, which in addition to Simmons includes Brent Woods Sebastian Bach, Vince Neil (MÖTLEY CRÜE, Zach Throne Mother Pearl, The Pink Floyd Experience), Cody Carpenter and Brian Tichy (Whitesnake, Billy Idol, Foreigner, Sass Jordan and Ozzy Osbourne).