“You celebrate the university for taking such a strong stand,” said Kevin Plank, Under Armour’s founder and chief executive, who added, “Notre Dame doesn’t need us when the sun is shining; they need us when it’s raining.”

Under Armour’s motto for the Notre Dame deal is Tradition Meets Performance, but that can be turned on its head: Each partner is perceived to have only one of those characteristics. Each partner is looking for what it lacks in the other. It is the basis for a lasting relationship, but it means the stakes are higher than usual.

Notre Dame also gives Under Armour immediate entree to a gigantic, passionate fan base — not to mention lots of airtime on NBC, which televises all the Fighting Irish home football games.

“I’m not saying we’ve been playing in single-A ball,” said Plank, whose company also outfits Auburn, South Carolina, Utah and others, “but we just signed the Yankees.”

After playing football at Maryland and discovering a need for moisture-wicking gear, Plank in 1996 founded Under Armour, the teenage arriviste of sports apparel that made a name for itself with undergarments. The company inserted itself into the wacky uniform race in 2003 by creating gear for Maryland that was even flashier than Nike’s at Oregon.

The Notre Dame-Under Armour partnership is compelling because it is complementary: the ultimate establishment (or stodgy) football program trying to adjust to the times by joining with the ultimate renegade (or showy) apparel company seeking gravitas. They may prop each other up; they may allow each other to fall.

Notre Dame reached the national championship game only two seasons ago and has looked impressive this season, starting 2-0 while being led by Golson, who was readmitted and has another year of eligibility. But nobody could confuse the current team — at least not yet — with the perennial powerhouse it once was.