During the twentieth century, the NCAA had no playoff for the major college football teams in the University Division, which became Division I in 1973 (and Division I-A in 1978). 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 fifty 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 twenty points for first place, nineteen for second, etc., the "overall" ranking was determined.
This season was historically significant because it was the first in which freshmen were eligible to play varsity football in the University Division. The NCAA had historically prohibited freshmen from varsity competition, except during the United States involvement in World War II. In 1968, the NCAA allowed freshman eligibility in the University Division 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 "University" and "College" divisions. For the 1973 season, the NCAA created the three-division structure that exists today with teams and conferences designated accordingly:
Five years later in 1978, Division I was subdivided (for football only) into I-A and I-AA. In 2006, these were renamed Division I FBS and FCS, respectively. Many of the teams and conferences now in FCS (Big Sky, Ohio Valley, SWAC, Yankee) were initially in Division II and moved up to I-AA.
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. For the first time, the Sugar Bowl was played at night on New Year's Eve, rather than New Year's Day afternoon. With two consecutive victories in the Orange Bowl, #9 Nebraska was invited to a third against #12 Notre Dame.