Dr. Holmes graduated from the University of Western Ontario, Faculty of Dentistry, where he obtained his D.D.S..  His four year residency in Oral and Maxillofacial Surgery (OMFS) was completed at the University of Rochester in New York whereupon he returned to a teaching position at the University of Toronto, Faculty of Dentistry, Department of Oral and Maxillofacial Surgery.

Dr. Holmes is currently Head of the Division of Oral and Maxillofacial Surgery at University of Toronto. He is also the Director of Undergraduate OMFS Teaching and the Surgical Director of the Graduate Surgical Orthognathic Surgery Program at the University of Toronto.