Its athletic teams are known as the Fighting Irish. Exactly where and how Notre Dame's athletic nickname came to be never has been perfectly explained. One story suggests the moniker was born in 1899 with Notre Dame leading Northwestern 5-0 at halftime of a game in Evanston, Illinois. The Wildcat fans supposedly began to chant, "Kill the Fighting Irish, kill the Fighting Irish," as the second half opened. Another tale has the nickname originating at halftime of the Notre Dame-Michigan game in 1909. With his team trailing, one Notre Dame player yelled to his teammates - who happened to have names like Dolan, Kelly, Glynn, Duffy and Ryan - "What's the matter with you guys? You're all Irish and you're not fighting worth a lick." Notre Dame came back to win the game and the press, after overhearing the remark, reported the game as a victory for the "Fighting Irish."

The most generally accepted explanation is that the press coined the nickname as a characterization of Notre Dame athletic teams, their never-say-die fighting spirit and the Irish qualities of grit, determination and tenacity. The term likely began as an abusive expression tauntingly directed toward the athletes from the small, private, Catholic institution. Notre Dame alumnus Francis Wallace popularized it in his New York Daily News columns in the 1920s.

The school has a comprehensive and nationally competitive Division I athletic program, but it is most famous for its football program. With 11 National Championships (most among Division 1A teams), Notre Dame football is considered one of the most storied college football programs in America. Notre Dame is a member of the Big East Conference in all sports except for football, in which it maintains its status as one of a small handful of Division I-A independents; and hockey, which is not sponsored by the Big East. Its hockey program competes in the Central Collegiate Hockey Association.