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 1926 college football season was the first in which an attempt was made to recognize a national champion after the season.
The 1927 college football season ended with the Illini of the University of Illinois (7–0–1) being recognized as champion under the Dickinson System. At season's end, the Rissler Cup was awarded to the team that finished first in the "Dickinson ratings", which considered strength of schedule, in that a win, loss or tie against a "strong" opponent was worth more than one against a lesser team, and the results were averaged.
The 1928 football season had both the USC Trojans and the Georgia Tech Golden Tornado claim national championships. USC was recognized as champions under the Dickinson System, but the Rose Bowl was contested between the No. 2 and No. 3 Dickinson-rated teams, California and Georgia Tech. The game was decided by a safety scored after Roy "Wrong Way" Riegels ran 65 yards in the wrong direction. Vance Maree blocked the ensuing punt which gave Georgia Tech a safety deciding the 8–7 win.
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 by two of three contemporary major selectors, while the third (Houlgate) named USC (10–2). Eight of nine retrospective selectors later also named Notre Dame and USC as No. 1 teams.
The 1930 college football season saw Notre Dame repeat as national champion under the Dickinson System, as well as claim the No. 1 position from each of the other three contemporary major selectors,. The post-season Rose Bowl matchup featured two unbeaten (9–0) teams, Washington State and Alabama, ranked No. 2 and No. 3, respectively. Alabama won the Pasadena contest, 24–0.
The 1931 college football season saw the USC Trojans win the Knute Rockne Memorial Trophy as national champion under the Dickinson System, as well as the No. 1 position from each of the other three contemporary major selectors. Rockne, who had coached Notre Dame to a championship in 1930, had been killed in a plane crash on March 31, 1931. For the first time, the champion under the Dickinson System also played in a postseason game. The 1932 Rose Bowl, promoted as a national championship game between the best teams of East and West, matched USC and Tulane, No. 1 and No. 2 in the Dickinson ratings. USC won, 21–12, and was awarded the Albert Russel Erskine Trophy.
The 1933 college football season saw the Michigan Wolverines repeat as winners of the Knute Rockne Memorial Trophy as national champion under the Dickinson System.
The 1934 college football season was the 66th season of college football in the United States. Two New Year's Day bowl games were initiated to rival the Rose Bowl Game. On February 15, Warren V. Miller and Joseph M. Cousins organized the New Orleans Mid-Winter Sports Association and by October, the group had enough funds to sponsor the Sugar Bowl. Meanwhile, W. Keith Phillips and the Greater Miami Athletic Club worked in November at a January 1 game for Florida, and the Orange Bowl was created.
The 1935 college football season was the last one before the Associated Press (AP) writers' poll was used in selecting the national champion. There were seven contemporary math system selectors that year who are informally recognized by the NCAA as "nationwide in scope". The Dickinson System, run by University of Illinois Professor Frank Dickinson, selected Southern Methodist University (SMU) as best in the nation. The Houlgate System, created by Carroll Everard "Deke" Houlgate Sr., also selected SMU. The contemporary Boand, Litkenhous and Poling math rating systems all selected Minnesota as the No. 1 team in the nation. The Dunkel System selected Princeton as its top team. The Williamson System, by Paul O. Williamson of New Orleans, ranked Texas Christian University first.
The 1936 college football season was the first in which the Associated Press writers' poll selected a national champion. The first AP poll, taken of 35 writers, was released on October 20, 1936. Each writer listed his choice for the top ten teams, and points were tallied based on 10 for first place, 9 for second, etc., and the AP then ranked the twenty teams with the highest number of points. In the first poll, Minnesota received 32 first place votes, and 3 votes for an additional 25 points, for a total of 345 altogether. Of the seven contemporary math system selectors, two chose Pittsburgh as the top team.
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" rule 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 was marked by the surprising abandonment of the two-platoon system and unlimited substitution by the NCAA rules committee in January in favor of the historic one-platoon system with its highly restrictive substitution rules. This radical rules shift made the 1953 season "The Year of the Great Adjustment," in the words of sportswriter Tommy Devine of the Detroit Free Press, in which teams scrambled to tighten their rosters and alter their strategies in accord with the more conservative "iron man" game.
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 their 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 1948 college football season finished with two unbeaten and untied teams: Michigan and Clemson. Michigan was the first-place choice for the majority of the voters in the AP Poll, but did not 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 one point in the Gator Bowl.
The 1947 college football season finished with Notre Dame, Michigan, and Penn State all unbeaten and untied, but the Fighting Irish of Notre Dame were the first place choice for 107 of the 142 voters in the final AP Poll in early December, and repeated as national champions. Michigan was selected for the top spot by six contemporary math systems.
The 1937 college football season ended with the Panthers of the University of Pittsburgh being named the nation's No. 1 team by 30 of the 33 voters in the Associated Press writers' poll. The AP poll was in its second year, and seven votes were taken during the final weeks of the 1937 season, starting with October 18. Each writer listed his choice for the top ten teams, and points were tallied based on 10 for first place, 9 for second, etc., and the AP then ranked the twenty teams with the highest number of points. With 33 writers polled, Pitt received 30 first place votes and 3 second-place, for a total of 327 points.
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 was also chosen by six contemporary math system selectors as a national champion; both teams won every game. Notre Dame was chosen by the Dickinson System and won the Knute Rockne Memorial Trophy.
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. Led by consensus All-American fullback John Kimbrough, the Aggies went undefeated at 11–0 and outscored their opponents by a combined total of 212 to 31, with the defense allowing just 54 first downs and 763 yards all season, or 1.71 yards per play. On New Year's Day, Texas A&M defeated Tulane, 14–13 in the Sugar Bowl.
The 1943 college football season was the 75th season of intercollegiate football in the United States. Played during World War II, the competition included schools from the Big Ten Conference, the Pacific Coast Conference (PCC), the Southeastern Conference (SEC), the Big Six Conference, the Southwestern Conference, and numerous smaller conferences and independent programs.