Hailing from Colorado, Brian Dietzen made his big-screen debut alongside Kelly Clarkson and Justin Guarini in From Justin to Kelly (2003) . He graduated with a BFA, majoring in acting, the University of Colorado at Boulder. He performed with the Colorado Shakespeare Festival for two years and spent five years performing contemporary theatrical works like "Equus" and "Same Time, Next Year" honoring him with the UROP grant for Outstanding Achievement in the Creative Arts.
Brian moved to L.A. where he was cast in the WB series My Guide to Becoming a Rock Star (2002) as a regular. Also, in L.A., he starred with Steve Rudnick in a two-man theatre production of "The Oldest Man in Show Biz" at the Hudson Stage, winning critical acclaim.
Toward the end of the first season, Brian began a recurring role on NCIS as the assistant M.E. Jimmy Palmer. He made periodic appearances at first, with his role growing in regularity as the series progressed.