Harold C. Baker graduated from the University of Toronto with a Bachelor of Applied Science in Electrical Engineering in 1954. He is a licensed Professional Engineer in the Province of Ontario. After serving three years as a telecommunications officer in the Royal Canadian Air Force in Radio Warfare, he joined an Ottawa firm of patent agents and qualified as a Canadian Patent Agent in 1959. He subsequently became registered as a Trade-mark Agent in 1962.

A member of the Intellectual Property Institute of Canada ((IPIC) and a Life Member of the Institute of Electrical and Electronic Engineers, he has served in numerous roles, including Chair of the Joint IPIC/Patent Office Liaison Committee, a founding member of the Computer Related Technology Committee (now the Information Technology Committee), and a former member of the Errors and Ommission Insurance Committee of the IPIC. He is a member of the Professional Engineers of Ontario, INTA, and AIPPI.

He has successfully prepared and prosecuted patent applications in the fields of computers, electronics, lasers, fiberoptics, telecommunications and related technologies.