The result was a run on khakis in Ann Arbor stores by fans of all ages.

Scott Hirth, an owner of M-Den, the university’s official merchandise retailer, said it saw increased sales of all khakis in its Ann Arbor stores this week (it sells both pleated and flat-front versions, as well as Dockers with a block M stitched into the back pocket for $70). “Let’s just say we sold way more khakis than your normal Monday,” Mr. Hirth said just before leaving to deliver boxes of khakis to its concession stand at Crisler Arena, where the basketball game was soon to begin.

Also busy was Brian Hilger, manager of M-Den’s Victors Collection boutique on State Street, near campus. “I saw all ages coming in wanting to buy Harbaugh’s look,” he said, pointing out the mannequin in the store window that had been dressed Harbaugh-like in a Michigan crew-neck sweatshirt, baseball cap and khakis (flat front).

Across the street at Van Boven Clothing, a men’s store that has catered to Ann Arbor’s best-dressed since 1921, business was also bustling in beige wear. “People were joking with us that we would be sold out of khakis this week, and then we started to actually see it happening,” said Alex McEachern, the store’s manager. “Now we want Jim to come in and buy a pair of our khakis,” he said, pointing out the store’s most high-end pair, a Peter Millar cotton trouser, also featuring the block M, for $135.

But it was Walmart that was anticipating the biggest post-announcement sales. Moments before the news conference on Tuesday, David Iaconelli, the manager at the Walmart 10 minutes from campus, was readying piles of Mr. Harbaugh’s old favorites: the pleated, baggy khakis his wife had lambasted (which, incidentally, now retail for $11.98, not $8). His plan was to move them into the section of the store selling University of Michigan merchandise. “The whole thing is just fun,” he added.

As fans approached Crisler for the basketball game against Illinois (the team’s Big Ten opener), looking forward to seeing Mr. Harbaugh in person, it was obvious many people had answered the khaki call.

“I’m wearing brand-new khakis I got for Christmas,” said Ryan Sekol, who graduated from Michigan in 2008, adding that he did not know the brand. His brother, Jim Abriel, a self-described lifelong Michigan fan, proclaimed his were pleated Dockers. When asked why they were wearing them, Mr. Sekol answered, “to support Harbaugh and because they are really comfortable.”