When original bassist Paul D'Amour left, Tool gave Justin a call. At first Justin turned them down. Peach had broken up about six months before, and he was forming a new band with the guitarist. Justin felt very loyal to his friend who he'd played with since he was 14. But then decided he couldn't deny himself the opportunity. Justin flew to the US, auditioned, and got the job. He beat out some stiff competition, which included Filter's Frank Cavanagh, KYUSS's Scott Reeder, Zaum's Marko Fox (who did the voice on Die Eier von Satan), and Pigmy Love Circus's E. Shepherd Stevenson.
After settling in the US, Justin married Ariadne Chancellor, on top of Mingus Mountain in Arizona on January 12, 1997.