It could have been any of the thousands of afternoons at Coach and Four Barber Shop over the past 43 years — ever since Jerry Erickson bought this State Street storefront halfway between downtown and the University of Michigan football complex now known as Schembechler Hall.

Three of the four barber chairs were occupied. The walls were adorned with taxidermists’ handiwork, including a deer head, along with uncountable artifacts of Michigan Wolverines football and hockey. A Cigar Aficionado magazine, a copy of Playboy and a few Sports Illustrateds were fanned out like a hand of poker on a table made of hockey-stick shafts. The minirefrigerator in the corner contained bottles of Molson and Yuengling.

But something was different this summer.

“We’re geeked, man, with that new coach,” Erickson, 71, said. “After the last seven years, I’ll tell you what — he’s brought some spirit back, and we needed that.”

He added, “Bo was one of my favorite customers, and that was one of the last times we had that.”

“Bo” was Bo Schembechler, who coached the Wolverines to a 194-48 record from 1969 to 1989. And “that new coach” is Jim Harbaugh, who played quarterback for Schembechler in the 1980s and who, after a successful decade with Stanford and the San Francisco 49ers, now has his old coach’s job.

In trying to grasp the effect that Harbaugh’s homecoming has had on the Michigan community, one could do worse than to visit the shop of the man who used to cut Schembechler’s hair.

“We’ve got Bo reincarnated in Harbaugh,” Don Fardig, a Coach and Four regular known as Digger, said as he stopped by for a beer. “He’s got more Bo in him than most people realize. He was trained by him and learned well.”

Gordie Todd, who has worked at the barbershop since October, said of the hiring: “It’s huge. Michigan football was the tip of the top. Last seven, eight years, it’s been a decline. Bringing him in has got everyone hopeful.”

To outsiders, the connection might seem dubious after so many years. But in this quintessential college town, where Todd once shaved a customer’s hair so that his head resembled the Wolverines’ winged helmet, Michigan football can seem as if it is everything. And if Schembechler is Michigan football, then Schembechler is everything.

“‘What would Bo do?’ is a real question among Michigan fans,” said John U. Bacon, Michigan football’s unofficial chronicler and the author of the new book “Endzone.” It is also a question, Bacon added, that has been “asked a lot during the past tumultuous decade.”

That decade was defined primarily by a feeling of malaise. In 2007, Lloyd Carr — a former Schembechler assistant whose one national title, in 1997, was one more than his mentor’s total — retired. Carr was followed by Rich Rodriguez and Brady Hoke, who combined for four winning records in seven forgettable seasons. Making matters worse for fans, a new athletic director, Dave Brandon, commercialized football in a manner that might have been standard elsewhere but was viewed as unseemly in Ann Arbor.

Brandon resigned in the middle of last season, and interim athletic director Jim Hackett fired Hoke when the season ended. One obvious favorite to succeed Hoke emerged — and it all went back to Schembechler, whose football progeny are the coaches and players who came up under him, including successors like Gary Moeller, Carr and Hoke.

Another such “Michigan man” was Harbaugh. A flier displaying Michigan’s 1979 schedule, taped to the mirror behind Erickson’s chair at Coach and Four, said it all. It featured a photo of Harbaugh’s father, Jack, who was Schembechler’s defensive backs coach.

The transitive principle applied: Harbaugh’s father coached under Schembechler, and Harbaugh played for Schembechler; therefore, Harbaugh is Schembechler; therefore, Harbaugh is everything.

Several Michigan fans pointed to Harbaugh’s introductory news conference in December as evidence that he had personified the Schembechler creed. Asked about the relevance of his track record performing “turnaround projects” on mediocre teams, Harbaugh said: “I’m not agreeing that it’s a turnaround. This is Michigan, and there are no turnarounds in Michigan. This is greatness, and there’s a long tradition of it.”

Another part of Harbaugh’s appeal has been his connection to the town. According to Bacon, before Harbaugh accepted the position, he asked Hackett for help getting his children into St. Francis Elementary School, which he had attended.

Harbaugh has visited Coach and Four with recruits since his return, but hewing to a tradition that dates to his student days, he has his hair cut by a different barber on the same block. That barber is Bill Stolberg. He is still there. He is also Erickson’s cousin.

“It works,” Stolberg, 76, said of the friendly competition between his shop, State Street Barbershop, and Erickson’s. “We’re better. I’m better.”

State Street Barbershop is smaller than Coach and Four, and more modestly decorated in Michigan tchotchkes, although its collection now includes a signed copy of the Sports Illustrated that featured Harbaugh on the cover last spring. In black marker, Harbaugh called Stolberg “the best in North America.”

“He’s built into this town,” Stolberg said.

Later that day, Bill Graves, 87, who was Harbaugh’s pediatrician in the 1970s, came into Coach and Four. He had spent the afternoon at a luncheon honoring Harbaugh.

“He went to the Ann Arbor Rotary Club and got a standing ovation — before and after,” Graves said as Erickson trimmed his brows.

Now that the season has begun, however, hard realities must be faced.

The team down the road, No. 5 Michigan State, has won six of its past seven meetings with Michigan. The archrival, No. 1 Ohio State, looks unstoppable. And in a college football landscape reshaped by millions of broadly distributed cable television dollars, among other factors, blue bloods like Texas, Nebraska and Michigan have faltered while relative upstarts like Oregon, Texas Christian and Baylor have been able to seize the spotlight.

In a recent interview, Hackett wondered whether Michigan fans’ sentimental attachments might be a double-edged sword, even as he insisted that Harbaugh was the best option for the university for football reasons.

“He was clearly the fan favorite,” Hackett said, “but what I didn’t know about hiring football coaches is that it could’ve been what had been hurting us — because Bo and his offspring did so well, the university’s ability to decide great coaches could have atrophied.”

The truth probably lay somewhere in the middle: Harbaugh was most likely the best coach Michigan could have hired because he is very good at what he does, but also because Michigan had unique access to him.

When he was hired, Harbaugh said coaching Michigan was “something that I’ve dreamed about.”

Fardig, nursing his beer, described it from Michigan fans’ perspective.

“This is the guy we’ve waited for for 10 years or whatever — since Lloyd left,” he said, adding, “If he’s not the guy, who is?”