After being an undefeated NCAA champion at 157 pounds as a junior for Iowa State, Gordon Hassman finished third and helped the Cyclones win their first NCAA team championship as a senior in 1965.

He was an Iowa state champion at 120 pounds for New Hampton High School in 1960, joining his father, Paul Hassman, who was a state champion for New Hampton at 155 pounds in 1933. Gordon finished second at 103 pounds in 1959 and third at 138 pounds in 1961. He had a career record of 95-13-4 and was a two-time Northeast Iowa Conference champion.

Hassman was a three-time All-American, finishing third in 1963, and a two-time Big Eight Conference champion for Iowa State. He was named the Outstanding Wrestler at the 1964 Big Eight tournament and finished with a career record of 90-5-1 for the Cyclones.

He competed in the 1964 Olympic tryouts and made the team as an alternate after finishing second.