Wallin's career began in Bodens IK, his hometown team. Having had a breakthrough in the 1995–96 season, he was picked up by the Swedish Elitserien team Brynäs. After spending some years with Brynäs, Wallin was drafted in the fourth round, 97th overall by the Hurricanes at the 2000 NHL Entry Draft and remained at the team until February 2010. During the 2004–05 NHL lockout, Wallin returned to his native Sweden, playing 39 games for Luleå. In 2006, he won his first Stanley Cup with the Carolina Hurricanes.