Wallin's career began in the WHL playing for the Red Deer Rebels.

In 1996 he was taken 1st (26th overall) by the Detroit Red Wings in the NHL Draft, then returned to the WHL and went on to be named the CHL Humanitarian of the Year in 1997.

Wallin received the Doug Wickenheiser Memorial Trophy back-to-back in 1996–97 and 1997–98 for being the WHL's Humanitarian of the Year, particularly for his efforts in raising the profile of mental health.

Wallin made his professional debut with the American Hockey League's (AHL) Adirondack Red Wings in 1998–99 and spent the majority of his first three professional seasons in the AHL, the final two with the Cincinnati Mighty Ducks.

After five seasons with the Red Wings, Wallin signed as a free agent with the Calgary Flames in the summer of 2003 and was sent back down the AHL to play for the Lowell Lock Monsters.