Prior to his professional career, Caldwell was an All-American defenceman and captained the University of Denver Pioneers to the 2004 NCAA Championship.

After two seasons in the SM-liiga with Ässät, Caldwell signed with fellow Finnish club, Lukko Rauma.

On May 7, 2013, Caldwell was signed as a free agent to a two-year contract with the Thomas Sabo Ice Tigers.

[3] In the 2014–15 season, Caldwell contributed with 23 points in 52 games from the blueline, however was unable to lift the Wild Wings into the playoffs.

On March 7, 2015, the Wild Wings opted not to offer Caldwell a new contract, rendering him a free agent.