Leo Cahill was born in Utica, Illinois and from his earliest days as a youth, was captivated by football. After a superb high school career, Leo attended the University of Illinois on a football scholarship, appearing in the 1947 Rose Bowl game.
His professional coaching career began in the early 1960s in Montreal, where Cahill was an assistant coach with the Montreal Alouettes football team. His move to Toronto shortly thereafter, saw him take over direction of the Toronto Rifles of the Continental Football League. He made the move to the Argonauts just before the 1967 season and immediately made them a force to be reckoned with. Cahill coached the Argonauts three separate times, and had two Grey Cup appearances in 1971 and 1987.
Leo Cahill is one of the biggest names in Argonaut and Toronto sports history. He will always be remembered as one of the finest, most colorful coaches in the game and perhaps the best recruiter of talent ever in the CFL. Since 2004, Cahill has been serving as "goodwill ambassador" with the Argonauts. He has five children, Steve, Christy, Terry, Lisa and Bettye.