Twellman attended Michigan State University where he played on the Spartans soccer team during its first years playing in the National Collegiate Athletic Association Division I. He was team captain in 1971, earning second team All American recognition that season.
In 1972, the Atlanta Chiefs selected Twellman in the first round of the North American Soccer League college draft. He spent two seasons in Atlanta. In 1973, the team was renamed the Atlanta Apollos when ownership changed.
The team folded at the end of the season and Twellman moved to the Boston Minutemen for the 1974 season.
