Kravitz was born in New York City, New York, the son of Roxie Roker, an actress, and Sy Kravitz, an NBC television news producer. Kravitz's father was of Ukrainian Jewish descent and his mother was of Bahamian descent. Though biracial, Kravitz identifies more with his Bahamian heritage and is widely recognized as an African American, although he still considers himself Jewish.

Kravitz grew up in the Upper East Side of Manhattan. He began banging on pots and pans in the kitchen, playing them as drums at the age of three. At the age of five, he wanted to be a musician. He began playing the drums and soon added guitar. Kravitz grew up listening to the music his parents listened to: R&B, jazz, classical, opera, gospel, and blues. In 1974, the Kravitz family relocated to Los Angeles. It was in Los Angeles that Kravitz was first introduced to rock music, listening to Led Zeppelin, Kiss, Aerosmith, Jimi Hendrix, David Bowie The New York Dolls, Pink Floyd, Cream, and The Who. Kravitz wanted to be a session musician. He also appeared as an actor in television commercials during this time.

At the age of 15, determined to have a music career, Kravitz moved out of his house. He stayed with friends, slept in friends' cars, and at one point was even sleeping in his Ford Pinto. Inspired by David Bowieand The New York Dolls, Kravitz adopted the nom de guerre, "Romeo Blue," a new persona complete with straightened hair, eyeliner and mascara, and blue contact lenses, and began performing. Kravitz's music at this time was heavily influenced by the synth-laden funk pop of Prince. With his first demo, Kravitz received offers from several record labels, including I.R.S. Records, but Kravitz was told he needed to change his music to either make it "black enough" to fit in with current radio-friendly R and B styles or to make it "whiter" to work as a rock artist.

In 1985, Kravitz's parents divorced which had a profound impact on him. His relationship with his father became extremely strained. Kravitz focused on his music to help him get through this period. With record labels still telling him his music wasn't "black enough" or "white enough," Kravitz decided to record an album on his own. He signed with Virgin Records in 1989.

Kravitz released his debut album Let Love Rule on September 19, 1989, a combination of rock and funk with a general 1960s vibe. Music critics were mixed: some felt Kravitz was a gifted new artist, others felt he was overpowered by his musical influences.

Kravitz identifies himself as both a Christian and a Jew, which he described both as "all the same to me". He also notes that spirituality "has been an important issue in my growth", given his upbringing by parents of different faiths. Such spirituality is prominently featured on many of his songs, such as the lyrics on his album Baptism, and having his back inscribed with a tattoo stating, "My Heart Belongs to Jesus Christ."

In 1991, Kravitz released his second album, Mama Said, which was his first album to reach the Top 40. Kravitz's biggest single yet, "It Ain't Over 'Til It's Over", went to #2 on the Billboard Hot 100. In 1993, Are You Gonna Go My Way was released, reaching #12 on the Billboard 200 and Kravitz earned a BRIT Award for best international male artist in 1994. The title track won a MTV Video Music Award for Best Male Video.

With 5 (1998), Kravitz embraced digital technology such as Pro Tools and samplers for the first time. 5 introduced his music to an even wider audience thanks to the hit single "Fly Away". He would win the first of his four consecutive Grammy for Best Male Rock Vocal Performance at the Grammy Awards of 1999. His cover version of The Guess Who's hit "American Woman" won him another Grammy at the Grammy Awards of 2000 and helped The Guess Who's song reach a new audience. Kravitz released a Greatest Hits album in 2000. It proved to be his most successful album, reaching #2 on the Billboard 200 and selling over 8 million copies worldwide. The single "Again" earned him his third consecutive Grammy for the Best Male Rock Vocal in the Grammy Awards of 2001.

Kravitz released his sixth album Lenny in October 2001. He won his fourth Grammy in 2002. Kravitz's seventh album Baptism was released in May 2004. The first single was "Where Are We Runnin'?"