Erickson graduated from EHS in 1965 and accepted a football scholarship to Montana State in Bozeman to play for head coach and was a member of the Sigma Alpha Epsilon fraternity. He was an effective undersized quarterback from 1966 to 1968, earning all-conference honors in the Big Sky. Immediately after his senior season, Erickson began his coaching career as a graduate assistant for the Bobcats in 1969. In 1970 at age 23, he was the head coach at Billings Central Catholic High School, staying for just a single season.