After leaving the service as a Lieutenant (junior grade) in 1945, Lahar played for the Buffalo Bills of the All-America Football Conference from 1946 to 1948[4] before beginning his college coaching career as an assistant under Otis Douglas at the University of Arkansas in 1950. In 1952, he became the 25th head coach at Colgate University in Hamilton, New York. In 1957, he succeeded Bill Meek at the University of Houston, where he spent five years, before returning to Colgate in 1962, making him the first man to return to a Division I head-coaching job after leaving for another school.[5] Following the 1967 season, Lahar retired from coaching and served as athletic director at Colgate. His overall coaching record at Colgate was 53–40–8.
Lahar was also assistant commissioner of the Southwest Conference. He worked at the now-defunct SWC from 1973 until his retirement in 1983. Upon his death in 2003, Lahar was buried in the Dallas-Fort Worth National Cemetery.