The NCAA was without a playoff for the major college football teams in the University Division, later known as Division I-A, during the 20th century. The NCAA recognizes Division I-A national champions based on the final results of polls including the "wire service", FWAA and NFF. The 1964 AP poll continued to rank only ten teams, compiling the votes of 55 sportswriters, each of whom would give their opinion of the ten best. Under a point system of 10 points for first place, 9 for second, etc., the "overall" ranking was determined.
The 1966 University Division football season was marked by some controversy as the year of "The Tie", a famous 10–10 game between the two top-ranked teams, Michigan State and Notre Dame on November 19. Both teams were crowned national champions by various organizations after the regular season concluded, and neither participated in bowl game. Alabama finished the regular season undefeated and was third in the AP poll, while Georgia was fourth. Alabama went on to win the Sugar Bowl in dominant fashion. During the 20th century, the NCAA had no playoff for the major college football teams in the University Division, later known as Division I-A.
In the 1968 NCAA University Division football season, the system of "polls and bowls" changed. The Associated Press returned to its pre-1961 system of ranking the Top 20 rather than the Top 10, and voted on the national champion after the bowl games, rather than before. During the 20th century, the NCAA had no playoff for the major college football teams in the University Division, later known as Division I-A.
The 1969 college football season was celebrated as the centennial of college football.
The 1977 NCAA Division I football season was one in which the top five teams finished with 11–1 records. Notre Dame, which beat top-ranked and undefeated Texas in the Cotton Bowl, became the national champion.
The 1929 college football season saw a number of unbeaten and untied teams. Purdue, Tulane, Notre Dame and Pittsburgh all finished the regular season with wins over all their opponents. Notre Dame was recognized as national champion under the Dickinson System and by a United Press writer while Pitt was considered a national champion by several others due to Pitt possessing a greater scoring differential over the two teams' only common regular season opponent. Following the season, Pitt traveled to Pasadena to meet USC in the Rose Bowl, at that time the only postseason college football game and held between the perceived best teams of east and west. Despite Pitt's losing 47–14 to the Trojans, as bowls were still considered exhibitions by many, college football historian Parke H. Davis, whose national championship selections are recognized by the official NCAA records book, named the Panthers as that season's national champion while several other retroactive selectors recognized by the NCAA records book have selected Notre Dame. Both Notre Dame and Pitt claim a national championship for the 1929 season and both are recognized in the NCAA Records Book and by College Football Data Warehouse.
The 1932 college football season saw the Michigan Wolverines win the Knute Rockne Memorial Trophy as national champion under the Dickinson System. Because the "Big Nine" conference didn't permit its teams to play in the postseason, however, the Wolverines were not able to accept a bid to the Rose Bowl. As such, the Pasadena game matched the No. 2 and No. 3 teams, USC and Pittsburgh, with the USC Trojans winning the East-West matchup 35–0.
The 1924 college football season was the year of the Four Horsemen as the Notre Dame team, coached by Knute Rockne, won all of its games, including the Rose Bowl, to be acclaimed as the best team in the nation. Notre Dame and Stanford were both unbeaten at season's end, with the Fighting Irish winning the Rose Bowl contest 27–10. The Penn Quakers were retroactively awarded a national championship by Parke H. Davis.
The 1956 NCAA University Division football season saw the University of Oklahoma Sooners finish a third consecutive season unbeaten and untied to again win the national championship.
The 1955 college football season saw the Oklahoma Sooners win the national championship after going 10–0–0. Although the final poll was taken before the postseason bowl games, Oklahoma played against the nation's other unbeaten and untied (10–0–0) team, the Maryland Terrapins, at the Orange Bowl in Miami, and won 20–6.
The 1954 college football season saw three teams finish unbeaten and untied, with Ohio State Buckeyes and the UCLA Bruins sharing the national championship as the No. 1 picks of the AP Poll and the UPI Poll, respectively. Although the winners of the Big Ten and the Pacific conferences normally met in the Rose Bowl, a "no repeat" prevented the two champions from meeting. UCLA, which had been in the Rose Bowl earlier in the year, was replaced by conference runner-up USC.
The 1953 college football season finished with the Maryland Terrapins capturing the AP, INS, and UPI national championship after Notre Dame held the top spot for the first nine weeks. The No. 4 Oklahoma Sooners defeated Maryland in the Orange Bowl, but there was no further polling after the November 30 results were released. However, Notre Dame was selected as the National Champions by 10 other polls and the Oklahoma Sooners received first in two polls. However, despite the team receiving National Championship rings, the University of Notre Dame does not recognize this title due to their policy of only recognizing AP or coaches' poll titles during the polling era (1936–present). Maryland was also the first champion of the Atlantic Coast Conference, which had been formed earlier in 1953 by seven colleges formerly with the Southern Conference. The year 1953 also saw the Michigan State Spartans, previously an independent, join the Big Nine Conference, which then became the Big Ten; MSU won the conference title in that first year and was the conference representative to the Rose Bowl, which it won 28–20 over UCLA.
The 1952 college football season ended with the unbeaten Michigan State Spartans (9–0) and Georgia Tech Yellow Jackets (12–0) each claiming a national championship from different polls. Michigan State finished first according to two of the "wire service" polls, which both placed Georgia Tech second. Georgia Tech was first in the International News Service poll. UP and INS merged in 1958 to form UPI. Although the Spartans became members of the Big Ten Conference in 1950, full participation did not come until 1953, and under the terms of their entry into the conference, they were not allowed to participate in postseason play. Georgia Tech won the Sugar Bowl on New Year's Day in New Orleans.
The 1951 college football season finished with seven unbeaten major college teams, of which five were unbeaten and untied. Ultimately, the Tennessee Volunteers were voted the best team by the Associated Press, followed by the Michigan State Spartans, with the Vols having a plurality of first place votes. Tennessee lost in the Sugar Bowl to the equally undefeated and untied No. 3 Maryland Terrapins, but the postseason games were not taken into account by the major polls. Tennessee, Maryland, Michigan State, and Illinois all claim national championships for 1951.
The 1950 college football season finished with the unbeaten and untied Oklahoma Sooners (9–0) being the consensus choice for national champion. On New Year's Day, however, the Sooners were upset by the Kentucky Wildcats in the Sugar Bowl. The Army Cadets, ranked No. 2 in the AP Poll, had been defeated in its final regular season game by 2–6 Navy, 14–2. However, the final poll had been issued on November 27, and the bowl games had no effect on Oklahoma's status as the No. 1 team.
The 1949 college football season finished with four teams that were unbeaten and untied-- Notre Dame, Oklahoma, California, and Army had won all their games at season's end. Notre Dame, however, was the overwhelming choice for national champion in the AP Poll, with 172 of 208 first place votes. The Fighting Irish did not participate in the New Year's Day bowl games, which were played on January 2, 1950.
The 1948 college football season finished with two unbeaten and untied teams; Michigan and Clemson. Michigan was the first place choice for the majority voters in the AP Poll, but didn't play in the postseason because of a no-repeat rule for Big Nine schools. Notre Dame, second in the AP Poll, tied USC 14–14 at the end of the regular season, but did not participate in any bowl per university policy at the time. Northwestern beat California 20–14 in the Rose Bowl, and Clemson defeated Missouri by a point in the Gator Bowl.
The 1946 college football season finished with the Notre Dame Fighting Irish crowned as the national champion in the AP Poll, the Georgia Bulldogs recognized as national champion by the Williamson poll and United States Military Academy named as national champion in various other polls and rankings. The Delaware Fightin' Blue Hens were recognized by the AP as the small college national champion. Notre Dame and Army both won all of their games, with the exception of their November 9 meeting at New York's Yankee Stadium, where they had played to a 0–0 tie in a No. 1 vs No. 2 matchup regarded as a "Game of the Century". Neither team played in bowl game that season.
The 1938 college football season ended with the Horned Frogs of Texas Christian University (TCU) being named the nation's No. 1 team by 55 of the 77 voters in the final Associated Press writers' poll in early December. Tennessee is also recognized as a national champion; both teams won every game.
The 1939 college football season concluded with the Aggies of The Agricultural and Mechanical College of Texas being named as the national champions by the voters in the Associated Press writers' poll.