From 1956 to 1958, he served as an assistant coach at
Brown University. He was an assistant coach at
Colgate University from 1959 to 1961. He joined the
Hamilton Tiger-Cats as an assistant coach and later offensive coordinator. In 1968, he became the fourth head coach of the Hamilton Tiger-Cats, replacing
Ralph Sazio. As head coach, he posted a 22–17–3 record. On January 5, 1971, he became the head coach of Harvard. He was head coach for 23 years amassing a record of 117–97–6. He led Harvard to five
Ivy League championships. When he retired in 1993, the 23 years that he coached at Harvard was the longest tenure in the school's 124 year football history. Restic had a friendly rivalry with
Yale coach
Carmen Cozza who served as the Bulldogs coach for all of Restic's time at Harvard. During their period of the college football rivalry, known as
The Game, Yale won 13 times to Harvard's 10. Restic served as
president of the
American Football Coaches Association in 1988.
Multiflex offense While coaching in Canada, Restic devised the multiflex offense, which encompassed numerous formations, blocking strategies and pass patterns, sometimes with shifts at the last moment. The idea was to confuse the opponents. Restic explained that it was designed to "create doubt in the best athletes." For example, he would line-up three receivers on one side of the field, and then have them sprint to the opposite side just before the snap. In 1979, a professor and former Harvard quarterback, Larry Brown, created a class titled Fundamentals of Multiflex Offense to explain the maneuvers of the strategy. Some of the students included the Crimson's defensive players. ==Personal life==