At Penn State, Mitinger was a two-way All-American player—the consummate 60-minute man, playing tight end and defensive end for Nittany Lions head coach, Rip Engle. He was part of the Penn State team that upset Number. 10-ranked Alabama in the 1959 Liberty Bowl—the school"s first bowl victory.
He also helped Penn State to victories over Oregon in the 1960 Liberty Bowl and Number.
13-ranked Georgia Technical (30–15) in the 1961 Gator Bowl and was selected to compete in the 1962 Hula Bowl.
After Penn State defeated Cal 30–15 in 1962, Cal coach Marv Levy called Mitinger "the best college football player in the United States."
Mitinger attended Greensburg-Salem High School in Greensburg, Pennsylvania.