The recurring guest role of Dr. Overlark has been described as 50 years old, and a ruthless advisor to Arliss Howard’s Governor Creighton Burrell. Cast as Dr. Overlark, John Fleck is a long-time character actor who has appeared in a wide array of television guest roles. Mr. Fleck is one of only three actors to have appeared in every installment of the Star Trek television franchise (albeit as a different character in each).