During Stewart’s athletic career at Cedarburg High School, he earned nine varsity letters while competing in three different sports -- baseball, basketball, and football.  He was an outstanding all-around athlete, whose greatest success came as a pitcher in baseball and as quarterback in football. 

Stewart lettered three times in football and was a member of Coach Vince Cibik’s 1951 and 1952 4-C Conference championship teams.  He was an exceptional quarterback who threw 16 touchdown passes during his senior year, a Cedarburg High School record at the time.  The 1953 Cedariel described Stewart as “Our great passer”.  He also earned a varsity letter as a member of the 1952-53 4-C Conference Champion basketball team.

After his graduation from Cedarburg High School, Stewart continued to play competitive baseball as a pitcher in the Land O’ Lakes Northern Division, throwing a no-hitter in both the 1954 and 1955 seasons

He was also a member of the Lettermen’s Club for each of his four years at CHS.