Donn played linebacker in 1950, '51, and '52. During that time he was named a two time All-American (in 1950 and consensus in 1952), making him the first in UCLA history. He was named MVP both in '50 and '52, and he was co-captain in '52. His jersey number (#80) has been retired by the team, and he was inducted into the National Football Foundation Hall of Fame in 1973, the same year he was inducted into the UCLA College Football Hall of Fame. In 1953 Donn was the first-round draft pick for the Los Angeles Rams. His football legacy continues through the "Donn D. Moomaw Award for Outstanding Defensive Player in USC Game", which is still given today. 
In 1993, he was forced to resign as a result of "sexual contact" with five women. In 1997, he was allowed to return to the pulpit on a full-time basis at the 800-member Village Community Presbyterian Church in Rancho Santa Fe. Prior to that position, Rev. Moomaw was allowed to serve as the guest preacher at St. Andrew's Presbyterian Church.