The 1972 NCAA University Division football season saw the USCTrojans, coached by John McKay, go undefeated and win the national championship as the unanimous choice of the fifty AP panelists. Eighth-ranked in the preseason, the Trojans were narrowly voted #1 in the first AP poll, and stayed out front for the rest of the year.
During the twentieth century, the NCAA had no playoff for the college football teams that would later be described as "Division I-A". The NCAA Football Guide, however, did note an "unofficial national champion" based on the top ranked teams in the "wire service" (AP and UPI) polls. The "writers' poll" by Associated Press (AP) was the most popular, followed by the "coaches' poll" by United Press International) (UPI). Through the 1973 season, the UPI issued its final poll in early December before the bowls, but since 1968 (and 1965) the AP Trophy was withheld until the postseason was completed. The AP poll in 1972 consisted of the votes of 50 sportswriters, though not all of them voted in every poll. Those who cast votes would give their opinion of the ten best teams. Under a point system of 20 points for first place, 19 for second, etc., the "overall" ranking was determined.
This season was historically significant because it was the first season in which freshmen were eligible to play varsity football. The NCAA had historically prohibited freshmen from varsity competition, except during the US involvement in World War II. In 1968, the NCAA allowed freshman eligibility in all sports, except football and basketball, and extended the rule to those sports effective with the 1972-73 academic year.
This was the last season for the NCAA's "University Division" and "College Division". For the 1973 season, the NCAA created the three-division structure that exists today with teams and conferences designated accordingly:
On September 9, however, in Los Angeles, Nebraska lost to unranked UCLA, 20–17, and dropped to 10th place. #2 Colorado beat California 20-10. #3 Ohio State was idle. #4 Arkansas played against #8 USC in Little Rock and lost, 31-10. #5 Penn State had not begun its season and fell to 6th. #7 Alabama, with a 35-12 over Duke in Birmingham, reached the Top Five. So, too, did #6 Oklahoma, which had not yet played a game. In the next poll, USC received 13 first place votes, and Colorado and Oklahoma had 12 apiece, but USC had a narrow lead in points, 779 to Colorado's 769. The poll was: 1.USC 2.Colorado 3.Ohio State 4.Oklahoma 5.Alabama
The poll was 1.USC 2.Oklahoma 3.Alabama 4.Ohio State 5.Nebraska
October 21: #1 USC beat Washington 34-7. #2 Oklahoma yielded its first touchdown of the season at Colorado, and eventually fell 20-14. #4 Ohio State won at Wisconsin 28-20.
#3 Alabama won at Tennessee 17-10. #5 Nebraska won at Kansas, 56-0, to continue its rise in the polls. #6 Michigan won at Illinois, 31-7, and returned to the Top 5. The poll was 1.USC 2.Alabama 3.Nebraska 4.Ohio State 5.Michigan
October 28: #1 USC won at Oregon, 18-0, its only shutout in a perfect season. #2 Alabama beat Southern Mississippi 48-11 in Birmingham. #3 Nebraska registered its 4th consecutive shutout, a 34-0 win at Oklahoma State. Including a 77-7 win at Army, the Cornhuskers had outscored their opponents 271-14 after an 0-1 start. #4 Ohio State beat Indiana 44-7. #5 Michigan beat Minnesota 27-19. The poll was 1.USC 2.Alabama 3.Nebraska 4.Michigan 5.Ohio State
November 4: #1 USC beat Washington State at a game in Seattle, 44-3. #2 Alabama defeated Mississippi State 58-14. #3 Nebraska won at Colorado, 33-10.
#4 Michigan won at Indiana 21-7. #5 Ohio State beat Minnesota 27-19. The poll remained unchanged at: 1.USC 2.Alabama 3.Nebraska 4.Michigan 5.Ohio State
November 11: #1 USC had the week off. #2 Alabama beat LSU at Birmingham 35-21. #3 Nebraska visited Iowa State and played to a 23-23 tie. #4 Michigan won at Iowa, 31-0. to extend its record to 9-0-0. #5 Ohio State lost at Michigan State, 19-12. #7 Oklahoma, which beat Missouri 17-6, returned to the Top Five. The poll was: 1.USC 2.Alabama 3.Michigan 4.Oklahoma 5.Nebraska
November 18: #1 USC beat #14 UCLA, 24-7. #2 Alabama beat Virginia Tech 52-13. #3 Michigan got past Purdue, 9-6. #4 Oklahoma won at Kansas 31-7. #5 Nebraska beat Kansas State 59-7. The Top 9 stayed unchanged. The Top Five:1.USC 2.Alabama 3.Michigan 4.Oklahoma 5.Nebraska
November 25: #1 USC and #2 Alabama were idle. #3 Michigan (10-0-0) and #9 Ohio State (9-1-0) met at Columbus, in a season ending game that would determine the Big Ten title and who would face USC in the Rose Bowl. Ohio State won, 14-11. #4 Oklahoma returned the favor of last year's Game of the Century, and beat #5 Nebraska 17-14 on the road in Lincoln. Oklahoma accepted a bid to the Sugar Bowl, where it would face #6 Penn State; Penn State had beat visiting Pittsburgh 49-27 to close its season 10-1-0. The poll: 1.USC 2.Alabama 3.Oklahoma 4.Ohio State 5.Penn State
December 2: #1 USC closed its regular season with a 45-23 win over visiting Notre Dame to finish at 11-0. #2 Alabama, at (10-0-0), was preparing to do the same as it met Auburn (8-1-0) in the annual Iron Bowl at the end of the regular season in Birmingham. The Auburn Tigers spoiled perfection, beating Alabama 17-16. #3 Oklahoma closed its regular season with a 10-1-0 record after a 38-15 win over Oklahoma State. #4 Ohio State and #5 Penn State had both finished their seasons. The final regular season poll was: 1.USC 2.Oklahoma 3.Ohio State 4.Alabama 5.Penn State. In 1972, only the Rose Bowl (Big Ten vs. Pac-8) and Cotton Bowl (SWC winner) had rigid conference tie-ins. Thus, Big 8 champion Oklahoma passed up an Orange Bowl invitation to play in the Sugar Bowl, while SEC champion Alabama passed the Sugar to meet Texas in the Cotton Bowl. For the first time, the Sugar Bowl was played at night on New Year's Eve, rather than New Year's Day. With two consecutive victories in the Orange Bowl, #9 Nebraska was invited to a third against #12 Notre Dame.
Many of the schools that are now in the NCAA's Division I FCS were ranked in the "college division poll", taken by both the UPI (coaches) and AP (a panel of writers). Both the UPI and the AP panel ranked Delaware (10-0-0) first, followed by Louisiana Tech (11-0-0).  (Louisiana Tech is now in Division I FBS, in the WAC.) The College Division was split into Divisions II and III in 1973, and the University Division became Division I.