In 1920, Theron Fouts became coach of the North Texas State Normal College-renamed North Texas State Teachers' College in 1922-football team. He served as coach from 1920-1924 and would later be named as dean of men and athletics director. The 1920s also witnessed the affiliation of the college with its first conference, the Texas Intercollegiate Athletic Association, in 1921 and an undefeated season in 1922. Fouts Field would later be built and named after Coach Fouts in 1952.
1931 brought North Texas their first conference championship under Coach Jack Sisco, who coached the team from last place to first place within a two year time span. During Coach Sisco's tenure throughout the 1930s, North Texas would continue to dominate, winning 76 games and six conference championships.
Due to the number of male students fighting in World War II, North Texas was unable to field a football team during the war years. The postwar seasons however sparked a UNT record with North Texas enjoying six consecutive winning seasons under the coaching of Odus Mitchell from 1946 to 1952. North Texas also enjoyed its first bowl win in the 1946 Optimist Bowl due to a last minute play.
The 1950s witnessed the desegregation of the North Texas campus and football team. Abner Hayes, one of the first black players on the North Texas football team, joined the team in 1956, the first year of undergraduate desegregation. By his senior year in 1959, Haynes ranked seventh in the nation in rushing, fifth in scoring, and led North Texas to the 1959 Sun Bowl. Another milestone achieved in the 1950s was the construction of Fouts Field in 1952, named after former coach Theron Fouts.
The move in the late 1950s to the Missouri Valley Conference propelled North Texas into the arena of "major" college football for the decade of the 1960s. The 1968 season in particular was an exciting one as the "Mean Green" defense made quite an impression on both fans and opponents alike. The defensive unit featuring players Richard Gill and Joe Greene, who anchored the unit, inspired the nickname "Mean Green," a moniker that has remained ever since to describe North Texas athletics. "Mean" Joe Greene was named a consensus All-American pick in 1968 and went on to have an illustrious career in the NFL, being named the 1969 NFL Rookie of the Year and a 10 time Pro Bowl selection. Greene was inducted into the NFL Hall of Fame in 1981. 1969 also witnessed North Texas quarterback Steve Ramsey achieve the NCAA Record for passing touchdowns in a career, throwing 69 in his time at North Texas.
The 1970s began disastrously for the Eagles with the 1972 season record of 1-10 marking a low point. Coach Hayden Fry was hired in December of 1972 to turn the program around. Over the next six seasons, he succeeded by obtaining a 40-23-3 record. Notable highlights of the 1970s include a 98 yard kickoff return by Sears Woods in a 1975 game with only 4:25 remaining to score a North Texas victory; and the 1977 season which witnessed a 10-1 record for the Eagles. The 1977 season also included a victory over SMU-the first North Texas win over SMU since 1933.
The demotion to Division I-AA status in the late 1970s due to attendence and financial woes served as the catalyst for North Texas to move into the Southland Conference becoming its eighth member in 1982. Coach Corky Nelson led the Eagles to victory in the Southland Conference Championships in 1983, 1987, and 1983 before falling in the NCAA I-AA playoffs in each of those years.
A push to re-join I-A Conference football was sparked in 1990. The final year of Southland Conference membership occurred in 1994 with the Eagles winning the Conference championship. 1995 witnessed the return of North Texas to Division I-A play with the Eagles joining the Big West Conference in 1996.