Regehr was signed as a free agent on July 6, 2004, as an undrafted player by the Calgary Flames, the team where his brother Robyn was playing.

During the 2004–05 NHL lockout Richie Regehr played for the Lowell Lock Monsters, who were the American Hockey League affiliate of the Flames.

In his first National Hockey League game on December 29, 2005, he dressed with his brother Robyn and scored an assist on the game-winning goal.

Regehr replaced Knights teammate Mark Giordano (who was recalled to the Calgary Flames) on the 2006 Canadian AHL All-Star team.

After four impressive seasons with Berlin and winning three German championships with the club, Regehr left to sign a two-year contract in the Swedish Elitserien with Modo Hockey on April 25, 2012.