Mac graduated from the Upper School in 1946, having been a strong athlete and captaining the first hockey team. He graduated from the University of Toronto in 1949 and joined his father's toy manufacturing business, eventually becoming chairman of the firm. Mac's involvement in the school has always been as a protagonist of financial support. His first role after his election to the board in 1967 was to serve on the Financial Support Committee. He was a major force in the creation of the Ridley Foundation, a leader for the Program of Excellence and a decisive strength in the creation of the Griffith Complex. Taking over board leadership in 1977, Mac guided Ridley through the creation of boarding facilities for girls, the development of the Performing Arts Centre, and the planning of the subdivision of the houses into smaller administrative units. "Mac's style was resourceful, persuasive, and tireless." His chairmanship from 1977 - 1981 was marked by success in the School's long road back to fiscal stability.