His outstanding quarterbacking skills caught the attention of Notre Dame coaches, leading him to play for the Fighting Irish from 1949 to 1951, starting for the 1951 squad that finished 7–2–1.

Upon his discharge in 1954, Mazur headed to Canada, where he spent one year with the BC Lions of the Canadian Football League before suffering a career-ending ankle injury.

[1] On January 22, 1962, Mazur was hired as backfield coach of the American Football League Buffalo Bills, spending seven seasons with the team as offensive coordinator, helping them capture AFL titles in both 1964 and 1965.

By his final year with Buffalo in 1968, Mazur had seen the team collapse with the worst record in professional football, a dubious distinction that helped them select O. J. Simpson in the NFL Draft.

However, after just one year working under Dick Vermeil, Mazur left in 1977 to join former Eagles assistant Walt Michaels, who had been hired as head coach of the New York Jets.