A two-time letterman for the Cornhuskers as a defensive end in 1965 and 1967, Ivan Zimmer was a contributor on Coach Bob Devaney's Big Eight championship teams in both 1965 and 1966.

In 1965, Zimmer was pressed into action when knee injuries knocked out veterans Mike Grace, Bill Haug and Langston Coleman.  Zimmer finished the year with 16 total tackles and recovered three fumbles to help the Huskers to a No. 3 final ranking and a trip to the national championship game with Alabama in the Orange Bowl.

Zimmer managed one tackle in limited playing time as a junior in 1966, when the Huskers finished with a 9-2 overall record and a trip to the Sugar Bowl to face Alabama again. 

He did not post a tackle as a senior in 1967, as the Huskers finished with a 6-4 record.

Personal
Zimmer is the son of Mr. and Mrs. Joseph Zimmer of Hammond, Ind. Ivan spent his prep career at Bishop Noll Institute playing for Coach John Quinn.