The regular season ended with three one-loss teams in BCS contention: Oklahoma, LSU and USC. USC ended the regular season ranked #1 and LSU #2 in both the AP Poll and the Coaches' Poll. USC lost one triple-overtime game at California, which finished 8–6; LSU had a 12-point home loss against a Florida team that went 8–5; Oklahoma, which had been ranked #1 for most of the season, fell to #3 after suffering a 35–7 defeat in the 2003 Big 12 Championship Game to Kansas State, which finished 11–4. Controversy erupted when the BCS computers selected Oklahoma–LSU as the BCS title game. During the bowl games, USC had a convincing 28–14 win over #4 Michigan in the Rose Bowl while LSU beat Oklahoma 21–14 in the Sugar Bowl (designated the BCS title game). USC remained #1 in the final AP Poll with 48 of the 65 votes, and LSU was ranked, by contractual obligation, #1 in the final Coaches' Poll, though three coaches did not follow instructions and voted USC #1 in that poll as well.
With the late arrival of highly touted quarterbackJohn David Booty, who left high school a year early to attend USC, the Trojans' 2003 recruiting class was considered by some to be the best in the country.
Its legacy included many NFL Draft picks over several years, including five first-round picks.
USC opened the season visiting Auburn University: the Tigers were also ranked in the top 10 and had been named a pre-season favorite to be the national champion by at least one major news organization. In his first start, quarterback Matt Leinart led the Trojans on a dominating 23–0 performance.