Berry came into the spotlight in 1988, when he teamed with Keith Emerson and Carl Palmer (of Emerson, Lake & Palmer fame) and formed the band 3. Their only album, To the Power of Three, drew much criticism for its radio-friendly and polished 80's sound, considering the progressive pedigree of both Emerson and Palmer. 3 disbanded in 1989 after a small tour supporting To the Power of Three. The first single released from the album, Talkin' Bout, penned by Berry, reached #9 on the Billboard Mainstream Rock Tracks chart.
Since the dissolution of 3, Berry has participated in several projects, including Tales from Yesterday, a tribute album to Yes. He was also involved in an abortive follow-up to GTR in which he replaced Steve Hackett. Material from this project and an unreleased second 3 album appeared on Berry's solo album Pilgrimage to a Point. Berry's current band Alliance is composed of Gary Pihl from the band Boston on guitar, David Lauser from the Sammy Hagar Band on drums and Alan Fitzgerald from Night Ranger on keyboards. Berry also has contributed songs to a number of film soundtracks, including the Anthony Michael Hall film Out of Bounds. In 1999, Berry produced and performed on The Wheel of Time, an album billed as a soundtrack to the Robert Jordan fantasy series The Wheel of Time.