Coin enrolled at the University of Michigan in 1968 and played for the school's all-freshman team that fall. He was a member of the Michigan Wolverines football team from 1969 to 1971.[1] Coin played for Michigan at a time when the school's head coach, Bo Schembechler, held the view that there would be no kicking specialists on his team and that a kicker had to be a football player first. Accordingly, and although his greatest talent lay in his kicking, he also played at the linebacker position.[2]
As a freshman in 1968, Coin played on Michigan's freshman football team.[1] As a sophomore in 1969, he was a backup linebacker and handled kickoffs for the Wolverines.[2] As a junior in 1970, he began the season handling kickoffs and field goal attempts and took over responsibility for extra points in the middle of the season.[2] On September 19, 1970, he kicked a 42-yard field goal that was, at the time, the longest field goal in Michigan football history.[2][3] Coin's 42-yard field goal broke a school record of 40 yards set in 1961 by Doug Bickle, and not surpassed until a 50-yard kick by Mike Lantry in 1973.[4]
As a senior in 1971, Coin set an NCAA record by successfully converting 55 of 55 extra points without a miss. He was also the team's leading scorer with 79 points.[5][6] He kicked a career-high nine extra points against Iowa on November 6, 1971, surpassing the prior season record of 50 extra points set by Al Limahelu of San Diego State.[5] Coin's 55 extra points in 1971 remains a Michigan single-season record.[2]
Coin also started two games at outside linebacker in 1971.[7] Over the course of his career at Michigan, Coin totaled 54 tackles and a fumble recovery. He also successfully converted 70 of 72 extra points and 13 of 27 field goal attempts.[2][6] On November 13, 1971, Coin preserved Michigan's undefeated record and clinched a Big Ten Conference championship for the school when he kicked two field goals against Purdue, including the game-winning field goal with 46 seconds left in the game.[8] His final game in a Michigan uniform was the 1972 Rose Bowl. Coin kicked a 30-yard field goal and an extra point in the Rose Bowl, but Michigan lost to Stanford, 13–12.[9]