Kwanten began acting on the television shows A Country Practice, Hey Dad..! and Spellbinder. In 1997, he joined the cast of the Australian soap opera Home and Away, playing lifeguard Vinnie Patterson. He eventually chose to leave the series in 2002, shortly after his character married and became a father. Kwanten had previously guest starred on the serial as Robbie Taylor in 1994. Moving to the United States, Kwanten was cast as Jay Robertson in Summerland (2004–05). He appeared in the films Flicka (2006), with Maria Bello, Alison Lohman, and Tim McGraw, and Dead Silence (2007), a horror film in which he played the leading role, Jamie Ashen.