McCarron went 20-of-28 through the air for 264 yards with no turnovers, hooking up twice with Amari Cooper on scoring passes as the Crimson Tide (13-1) dominated from start to finish in posting a resounding win for their second straight BCS national championship.
Eddie Lacy rambled for 140 yards on 20 carries, scoring both rushing and receiving touchdowns, while Cooper finished with six grabs for 105 yards in the season-ending victory.
T.J. Yeldon provided 108 rushing yards and a score on 21 carries for the victors.
On defense, Alabama held the Fighting Irish to just 32 rushing yards as the Crimson Tide reeled off a fourth straight win following their only loss of the season Nov. 10 against Texas A&M.
Everett Golson completed 21-of-36 passes for 270 yards, a touchdown and an interception for the Irish (12-1), whose hopes for a perfect season and their first national title since 1988 were dashed.