At the age of sixteen, Lennon, along with Lenny Kravitz, co-composed the tune "All I Ever Wanted" for the 1991 collection "Mama Said." Four years later, Lennon had shaped the band IMA (with Sam Koppelman and Timo Ellis) to back up his mother on her collection "Rising." Lennon also showed up on film, appearing in Michael Jackson's Moonwalker in 1988 and depicting a youngster having dreams about different M. C. Escher works of art in the Sony produced 1990 particular short film "Infinite Escher."

In 1996, Yuka Honda and Miho Hatori were welcomed by Yoko Ono to remix the tune "Talking to the Universe" for a "Rising" remix extended play titled "Rising Mixes." They met Lennon and welcomed him to go along with them on a visit as a bass player. Lennon's solo record debut "Into the Sun" was released in 1998. A music video for "Home," the album's single, was produced and directed by Spike Jonze and was promoted heavily on MTV. "Into the Sun" was produced by Cibo Matto member Yuka Honda, whom Lennon acknowledged as the album's inspiration. As the album was being produced, Sean and Yuka struck up a friendly and creative relationship.

In the long run, this relationship prompted Lennon to contribute to a side-venture known as Butter 8 and became a band member. Lennon played bass for the group on tour, appeared with them on television, played bass, and sang vocals on their EP entitled "Super Relax." Through his relationship with Cibo Matto, Adam Yauch (of the Beastie Boys) got to know Lennon. He communicated an enthusiasm toward his music and induced him to sign up with Grand Royal Records.