Carter made his provincial debut for Canterbury in 2002, and in 2003 was signed by the Super Rugby side the Crusaders. Initially playing mainly at second five-eighth Carter reached the final of the Super 12 competition with the Crusaders in 2003, 2004, 2005 and 2006. Although they lost the 2003 and 2004 finals, in 2005 Carter had moved to first five-eighth. He regularly played with first-five eighth Andrew Mehrtens before Mehrtens left the team following their 2004 season. In 2005 and 2006 the Crusaders won the competition, and in the 2006 season Carter scored the most individual points for a player in one season with 221.