Following his honourable discharge in 1953, Cahill returned to his
alma mater, where he earned his master's degree and served as an assistant freshman football coach. After two seasons with the
South Carolina Gamecocks, Cahill moved to the Canadian Football League in the 1960 as an assistant coach with the
Montreal Alouettes. In 1965, he became head coach of the
Toronto Rifles of the
Continental Football League. Under Cahill's leadership, the Rifles compiled a 20–8 record and won the Eastern Conference title in 1965. In his first season as coach, Cahill led Toronto to its first playoff appearance since 1961. In 1971, he led the Argonauts to their first
Grey Cup appearance in 19 years and won the
league's coach of the year award. The following year, the Argos went 3–11 and missed the playoffs for the first time under Cahill. On November 9, 1972, Cahill was fired by Toronto Argonauts owner
John W. H. Bassett. Following his dismissal, Cahill wrote a book,
Goodbye Argos, with sportswriter
Scott Young that was critical of the Argonauts organization, specifically the team's board of directors and general manager
John Barrow, as well as his former boss in Montreal,
Jim Trimble, and
Hamilton Tiger-Cats president
Ralph Sazio, who he accused of interfering with his getting the Alouettes head coaching job in 1973. In 1974, Cahill was named general manager of the
Toronto Northmen of the
World Football League, which were owned by Bassett's son,
John F. Bassett. Cahill and Bassett signed three of the
Miami Dolphins top players –
Larry Csonka,
Jim Kiick, and
Paul Warfield. The team ending up moving to
Memphis, Tennessee due to
pressure from the federal government and became the Memphis Southmen. In 1975, Cahill left Memphis to become GM of another WFL team –
Chicago Winds. After the league folded, Cahill returned to Toronto as the chief operating officer of the
North American Soccer League's
Toronto Metros and also worked as a sports commentator for
CHUM. On December 20, 1976, Cahill was rehired as head coach of the Toronto Argonauts. He led Toronto to a 6–10 record in 1977 and was fired following a 3–6 start to the 1978 season. In 1979, Cahill began working as a sports commentator for
CFGM, a radio station in
Richmond Hill, Ontario. In 1981, he and
Ron Lancaster replaced
Russ Jackson on
CBC's coverage of the CFL. In 1986, Cahill returned to the Argonauts a second time, this time as general manager. He was hired by team president Ralph Sazio, whom Cahill had an acrimonious relationship with. It was hoped that Cahill's hiring would help increase ticket sales for the struggling franchise and that as a media personality, he would be able to help with marketing as well as football operations. That year the Argos, led by quarterback
J. C. Watts, finished first place in the
East Division. In 1987, Watts left football due to his displeasure with Cahill. Following bitter contract negotiations, Watts stated that he would not "let incompetent, insecure people like Leo Cahill hold the key to my future; I won't let a fool like that intimidate me" and returned to his hometown of
Oklahoma City, where he owned highway construction company, worked public relations for a high school, and was youth director of his church. Toronto went 11–6–1 without Watts and played in
that year's Grey Cup. Following the 1988 season, the team was purchased by
Harry Ornest, who chose to retain Sazio and not renew Cahill's contract. After leaving the Argonauts, Cahill worked as a leasing manager for Toronto auto firm, was a motivational speaker, and was a scouting consultant for the
San Francisco 49ers. In 1996, he returned to the CFL as vice-president of operations for the
Ottawa Rough Riders. In this role, Cahill oversaw football operations as well as marketing and public relations. The team folded at the end of the season. From 2004 onward, Cahill served as goodwill ambassador for the Argonauts. Cahill was inducted into the
Ontario Sports Hall of Fame in 2013 in recognition of his contributions to the Argonauts franchise. == Death ==