Brian Dietzen is an American actor who has played the supporting role of Dr. Jimmy Palmer on NCIS since 2004.

[5] Later, he studied theatre at the University of Colorado at Boulder's Bachelor of Fine Arts program.

[6] Dietzen has appeared in productions of Equus and Waiting for Godot and joined The Colorado Shakespeare Festival for two years.

He performed in the film From Justin to Kelly and has had a recurring role as Dr. Jimmy Palmer, a medical examiner's assistant, later Chief Medical Examiner on the CBS series NCIS, since the first season episode, "Split Decision".

Starting in season 10, he is a regular cast member with Dietzen also appearing in the opening credits.