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 1992 NCAA Division I-A football season was the first year of the Bowl Coalition and concluded with Alabama's first national championship in thirteen years—their first since the departure of Bear Bryant. One of Bryant's former players, Gene Stallings, was the head coach, and he used a style similar to Bryant's, a smashmouth running game combined with a tough defense.
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 a 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.
The 1973 NCAA Division I football season was the first for the NCAA's current three-division structure. Effective with the 1973–74 academic year, schools formerly in the NCAA "University Division" were classified as Division I. Schools in the former "College Division" were classified into Division II, which allowed fewer athletic scholarships than Division I, and Division III, in which athletic scholarships were prohibited.
The 1906 college football season was the first in which the forward pass was permitted. Although there was no clear cut national championship, there were two teams that had won all nine of their games as the 1906 season drew to a close, the Princeton Tigers and the Yale Bulldogs, and on November 17, 1906, they played to a 0–0 tie. St. Louis University finished at 11–0–0. The Helms Athletic Foundation, founded in 1936, declared retroactively that Princeton had been the best college football team of 1906. Other selectors recognized Yale as the national champions for 1906.
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 all three of the contemporary major selectors. Houlgate would later name USC (10–2) on the basis of post-season play. 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 1932 college football season saw the Michigan Wolverines win the Knute Rockne Memorial Trophy as national champion under the math-based 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 other four contemporary math system selectors all selected USC as national champion. This was also the last season NFL would use college football rules.
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 1912 college football season was the first season of the modern era of college football, as the NCAA implemented changes to increase scoring:
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 1923 college football season saw several teams finish their seasons unbeaten and untied. As such, numerous schools claim a national championship for the 1923 season. Illinois and Michigan, both members of what is now the Big Ten Conference, finished with records of 8–0 and were selected as national champion by multiple selectors. Illinois featured break-out star Red Grange. Ivy League teams Yale and Cornell also had undefeated seasons. Cornell was selected as national champion by one selector.
The 1953 college football season was marked by the NCAA Rules Committee's revocation of the two-platoon system and unlimited substitution rules 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 traditional "iron man" game.
The 1908 college football season ran from Saturday, September 19, to November 28. The Penn Quakers and the Harvard Crimson each finished the season unbeaten but with one tied. The LSU Tigers went unbeaten and untied against a weaker opposition. All three teams were named national champions retroactively by various organizations. Only Pennsylvania officially claims a national championship for the 1908 season. Kansas also went undefeated, but did not make a claim for the national championship.
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 1909 college football season was the first for the 3-point field goal, which had previously been worth 4 points. The season ran from Saturday, September 25, until Thanksgiving Day, November 25, although a few games were played on the week before.