Sonntag was a first-team All-Great Lakes Intercollegiate Athletic Conference Defensive Team selection at linebacker during the 1974 campaign. During the 1974 campaign, he compiled a school-record total of 30 tackles in a single-game against Eastern Illinois (10/26). His 18 solo stops in that contest also stands as a school single-game mark to date. Sonntag, who was known for his great lateral pursuit and his nose for the football, led Ferris in total tackles three consecutive seasons. He garnered a personal career-high 166 stops in 1972, which included 98 solo tackles and 68 assists. In 1973, Sonntag registered 130 total tackles, including 78 unassisted efforts and 52 assisted stops. He concluded his career with 92 solo tackles and 31 assists for 123 total tackles as a senior (1974). FSU won its final five games of the campaign to finish 6-4 under head coach Nick Coso in 1972, which was one victory shy of matching the school's record at the time for total wins. Sonntag, who was elected a team captain as a senior, was an All-NAIA District 23 pick three times. The 6-0, 190-pound Ann Arbor native earned four varsity letters at FSU after an outstanding prep career at Pioneer High School. Sonntag, who was a prep gridiron MVP, began his Bulldog career in 1969 and returned for his sophomore season in 1972 after a two-year leave for service in the Army. FSU compiled a 6-4 mark in his freshman campaign (1969) under coach Bob Leach. Sonntag now serves as sheriff of Mecosta County and lives in Big Rapids with his wife, Joyce. The couple has two children.