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.
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 NCAA did recognize a national champion based upon the final results of "wire service" polls. The "writers' poll" by Associated Press (AP) was the most popular, followed by the "coaches' poll" by United Press International) (UPI). Prior to 1965, both services issued their final polls at the close of the regular season, but before teams competed in bowl games. For the 1965 season, the AP took its final poll after the postseason games, an arrangement made permanent in 1968. The Associated Press presented the "AP Trophy" to the winner.
The 1958 NCAA University Division football season was notable in that it was the first to feature the two-point conversion. On January 13, 1958, the eleven-man NCAA Rules Committee unanimously approved a resolution to allow teams to choose between kicking an extra point after a touchdown, or running or passing from the three-yard line for two points. University of Michigan athletic director Fritz Crisler said at the meeting in Fort Lauderdale, "It's a progressive step which will make football more interesting for the spectators," adding that the rule "will add drama to what has been the dullest, most stupid play in the game."
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 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 1930 college football season saw Notre Dame repeat as national champion under the Dickinson System, and a post-season Rose Bowl matchup between two unbeaten (9–0) teams, Washington State and Alabama, ranked No. 2 and #3, respectively. Alabama won the Pasadena contest, 24–0.
The 1925 college football season ended with no clear national champion. At the close of the season, noted sports writer Billy Evans described the championship contest as "a dead heat" among Dartmouth, Tulane, Michigan, Washington, and Alabama.
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.
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 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 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 AP Poll, and repeated as national champions. Michigan went on to meet USC in the Rose Bowl and won 49–0, while Penn State was tied 13–13 by SMU in the Cotton Bowl Classic, and Notre Dame didn't participate in the postseason. An unofficial post bowl AP poll was conducted with Michigan and Notre Dame as the only options and Michigan won by a vote of 226 to 119.
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.
The 1940 college football season ended with the Gophers of the University of Minnesota being named the nation's No. 1 team and national champion by the AP Poll, and the Stanford University Indians in second, with the two teams receiving 65 and 44 first place votes respectively. 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. Minnesota, Stanford, Boston College, and Florida State all claim 1940 as a national championship season.
The 1941 college football regular season was the 73rd season of intercollegiate football in the United States. Competition included schools from the Big Ten Conference, the Pacific Coast Conference (PCC), the Southeastern Conference (SEC), the Big Six Conference, the Southern Conference, the Southwestern Conference, and numerous smaller conferences and independent programs.
The 1945 college football season finished with the undefeated United States Military Academy, more popularly known as "Army", being the unanimous choice for the nation's number one team by the 116 voters in the Associated Press writers' poll. The runner up was the undefeated Alabama Crimson Tide, followed by the United States Naval Academy, more popularly known as "Navy". In 2016, the American Football Coaches Association retroactively named the Oklahoma A&M Cowboys national champion for 1945.