Tredway attended North Park College in Chicago before transferring to Augustana. After graduating in 1957, he earned a master's in history from the University of Illinois, a bachelor of divinity degree from Garrett Theological Seminary, and a doctorate in history from Northwestern University.

He served as a student pastor but did not take a call to the ministry. In 1964, Tredway returned to Augustana as a history instructor. He was named academic dean in 1970 and president five years later. He was president of Augustana College from 1975 to 2003.