Seymour is one of four children born to parents who were educators. Brother Mark fronts a band called Hunters & Collectors and sister Helen teaches music. Along with sister Hilary, they entertained at gatherings in the region of Victoria during their childhood. Upon his graduation from high school, Seymour attended a Melbourne art school, where he remained for five years. His art background enabled him to create the album covers for Crowded House. He also contributed to the band's costumes and some of their videos. Seymour learned how to play bass without any formal lessons, taking up the instrument during art school.
Paul Hester and Neil Finn, fellow Crowded House band members, were ending their association with a band from New Zealand called Split Enz in 1984. They were kicking off a final tour to end their dozen years together. After learning that Hester and Finn needed a bassist for their new group, Seymour approached Finn at a party and secured an audition, winning a spot in Crowded House. The band was formerly known as the Mullanes.
The Australian bassist wed Brenda Bentleigh, an American, in 1989. The marriage ended in 1993. Seymour toured with brother Mark following the release of the latter's King Without a Clue album, which he also played on. ~ Linda Seida, Rovi