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 (later subdivided for football only in 1978 (I-A and I-AA) and renamed in 2006 into today's Division I FBS and FCS). 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.
In its inaugural season, Division I had two NCAA-recognized national champions, and they faced each other at year's end in the Sugar Bowl on New Year's Eve. The New Orleans game matched two unbeaten teams, the Alabama Crimson Tide (11–0), ranked No. 1 by AP and UPI, and the Notre Dame Fighting Irish (10–0), ranked No. 3 by AP and No. 4 by UPI.
While both wire services ranked Alabama first at the end of the regular season, the final AP poll was after the bowl games. By agreement with the American Football Coaches' Association, however, UPI bestowed its championship before the postseason bowl games, and Alabama was crowned champion by UPI on December 4. UPI ranked Notre Dame fourth: one coach had given the Irish a first place vote, compared to 21 for Alabama. (In the next season, the final coaches' poll was after the bowls.)
In a game where the lead changed six times, Notre Dame won by a single point, 24–23, to claim the AP national championship. During the 20th century, the NCAA had no playoff for major college football teams that would become 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). In 1973, the UPI issued its final poll before the bowls, but the AP Trophy was withheld until the postseason was completed. The AP poll in 1973 consisted of the votes of as many as 63 sportswriters and broadcasters, though not all of them voted in every poll. UPI's voting was made by 34 coaches. 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.
LSU at Tulane, December 1
- December 1: No. 1 Alabama shut out Auburn in Birmingham 35–0, avenging Auburn's shocking upset in the previous year, to close the regular season with an 11–0 record. No. 2 Oklahoma won at Oklahoma State 45–18 to finish 10–0–1. No. 3 Ohio State and No. 4 Michigan had already finished their season, tied against each other but undefeated against all other opponents. No. 5 Notre Dame won at Miami (Florida) 44–0, ending the regular season at 10−0.
- Elsewhere, Bluebonnet Bowl-bound Tulane defeated No. 8 LSU 14–0 to end a 25–year winless drought in the Battle for the Rag in the final meeting at Tulane Stadium, leaving both the Green Wave and Bayou Bengals 9–2. Also, the 4–7 Navy Midshipmen trounced the Army Cadets 51–0. The Cadets completed one of their worst season in their football program history, with an imperfect 0–10 record.
In the final regular season poll, the top six schools were unbeaten: No. 1 Alabama (11–0), No. 2 Oklahoma (10–0–1), No. 3 Notre Dame (10–0), No. 4 Ohio State (9–0–1), No. 5 Michigan (10–0–1), and No. 6 Penn State (11–0). The other major college unbeaten, Miami (Ohio) (10–0), was No. 15.
Alabama and Notre Dame accepted invitations to play in the Sugar Bowl for the national championship. Oklahoma was on probation for having used an ineligible player (Kerry Jackson) in three 1972 games and was ineligible to play in a bowl game; therefore, the Orange Bowl featured independent Penn State and SEC runner-up LSU (No. 13 in the final poll) rather than a Big 8 team. Because Big Ten rules allowed only one team to participate in postseason play, Michigan was forced to stay home while Ohio State matched up against No. 7 USC in the Rose Bowl. No. 11 Texas Tech had an impressive 10−1 record, but an early-season loss to Texas cost the Red Raiders the SWC championship and the conference's automatic Cotton Bowl bid. The eighth-ranked Longhorns struggled in non-conference play but blew through their SWC opponents for their sixth straight title, with an incredible 40−2 conference record since 1968. They would play the Big 8 runner-up, No. 12 Nebraska, in the Cotton Bowl.
Monday, December 31, 1973
Tuesday, January 1, 1974
Alabama and Notre Dame had never met in a college football game before their encounter in the Sugar Bowl, which was played on New Year's Eve at Tulane Stadium, with kickoff at 7:15 pm CST. Two legendary coaches, Bear Bryant and Ara Parseghian brought their teams to New Orleans, and the game was a thriller. The Irish scored first, but missed the extra point. After Alabama took a 7–6 lead, freshman Al Hunter returned the ensuing kickoff 93 yards for a touchdown, and a two-point conversion put Notre Dame up 14–7. Alabama went ahead 17–14 in the third, but a fumble on their own 12-yard line gave the Irish a chance to make it 21–17. In the fourth quarter, Bama got back the lead on a trick play, as quarterback Richard Todd handed off to running back, Mike Stock, who then fired a touchdown pass back to Todd; but Bill Davis, who had made 51 of 53 extra point attempts in his career, was wide right, and the score stayed 23–21. In the final minutes, Notre Dame's Bob Thomas (who had missed the earlier point after try) kicked a 19-yard field goal that gave the team the 24–23 win. Asked whether Notre Dame would be voted No. 1, Coach Parseghian replied, "Certainly. What was the final score?"
The final AP writers' poll was split. Notre Dame received a majority of the first place votes, 33 out of 60, followed by No. 2 Ohio State (11 votes) and No. 3 Oklahoma (16 votes, but fewer points overall). The fourth spot (held by Notre Dame in the final UPI poll) went to Alabama. UPI, who crowned Alabama as national champion at the end of the regular season, would begin holding the coaches' poll after the bowl games beginning with the 1974 season.
Running back John Cappelletti had the third best year in Penn State history when he gained 1,117 yards rushing in 1972. As a senior in 1973, he had the second best year in school history rushing for 1,522 yards. In his two-year running career, he gained 100 yards in the thirteen games and had a career total of 2,639 yards and twenty-nine touchdowns for an average of 120 yards per game and 5.1 yards per carry. Cappelletti's acceptance speech on December 13 at the Heisman Dinner (with new Vice President Gerald Ford next to him on the dais) was considered the most moving ever given at these ceremonies, as he honored his 11-year-old brother Joey, a victim of leukemia.
- John Cappelletti, RB - Penn State, 1,057 votes
- John Hicks, OT - Ohio State, 524
- Roosevelt Leaks, RB - Texas, 483
- David Jaynes, QB - Kansas, 394
- Archie Griffin, RB - Ohio State, 326
- Randy Gradishar, LB - Ohio State, 282
- Lucious Selmon, NG - Oklahoma, 250
- Woody Green, RB - Arizona State, 247
- Danny White, QB - Arizona State, 166
- Kermit Johnson, RB - UCLA, 122
- Tony Dorsett, RB - Pittsburgh, 118
- Lynn Swann, SE - USC, 108
- Anthony Davis, RB - USC, 104
- Condredge Holloway, QB - Tennessee, 98
- Leaks, Davis, and Holloway were juniors, Griffin a sophomore, Dorsett a freshman