Ingwersen served as an assistant coach at Illinois under Bob Zuppke from 1921 to 1923, the team again winning the college national championship in 1923.

[1] Belting offered Ingwersen a three-year contract, making him the 12th coach in Iowa football history.

Ingwersen's appointment was unanimously approved by the athletic board, although the selection was opposed by some Iowa alumni at the time.

Second, Ingwersen was perceived as a "traitor" by some Hawkeyes who felt that despite growing up in Illinois he was a native-born Iowan who turned his back on the state to play and coach for the Illini.

Things looked bleak at first, however, when Red Grange returned the opening kickoff 89 yards for a touchdown.

Iowa was suspended from athletic participation in the Big Ten, effective January 1, 1930, in the wake of a recruiting scandal that stretched back to the Howard Jones era.

After agreeing to suspend current players who had been paid from an alumni slush fund and to fire athletic director Belting, who was implicated in the scheme, Iowa was reinstated a month later.

In 1932 Ingwersen went to Louisiana State University as the number one assistant coach to Biff Jones, a lifelong friend.

[5] After the war, Ingwersen again became an assistant coach at his alma mater, the University of Illinois, this time under Ray Eliot.