Dr. Mark Donahue is the son of Peter Donahue and Kathleen (Carney) Donahue (retired Ilion High Math teacher). Both of his parents were Ilion High School Class of 1966 graduates. Mark grew up with his siblings, Paul, Kate and Sarah Donahue, on South Fifth Avenue, Ilion. He attended St. Lawrence University where he earned a Bachelor's Degree in Biology. He continued his studies in Dental School at the University of Buffalo and graduated in 2003. After Dental School, Dr. Donahue completed a residency program at the Veteran's Administration Hospital in Buffalo.

Dr. Mark Donahue and his wife Mary and their children; Kayleigh, Elionor, Shawn, Meagan and Kevin, reside in Amherst. He is a partner in the dental practice at Sheridan Family Dentistry, in Tonawanda, NY. Dr. Mark Donahue is the grandson of Dr. Theodore Carney IHS 1936.