As he has taken charge of the University of Michigan football team, Jim Harbaugh’s zany zealotry has made him either beloved or loathed. Patrick Semansky / AP

Michigan football fans are fanatical about their college team. It bonds almost anyone, anywhere, automatically. In 1975, I moved to Mozambique, then a scenic colony on the Indian Ocean, where a ten-year guerilla war was ending a half millennium of Portuguese rule and, in turn, igniting challenges to white-minority regimes across southern Africa. It was a historic time, and I needed a telephone to report on it. Impossible, the post, telephone, and telegraph agency told me—the waiting list was nine years long. I worked through layers of bureaucracy at its headquarters—pleading, cajoling, pressing, and flirting—until I found someone who spoke English with an American accent. He, too, said no. I was about to leave his office when, in one last stab, I noted his accent and asked where he had learned English. “The University of Michigan,” he said. Bingo. I told him I was an Ann Arbor girl, born, raised, and educated.

“If you can sing ‘Hail to the Victors,’ ” he replied, skeptically, “I’ll give you a phone.” I stood on a chair and belted out the Michigan fight song. Then we talked Michigan football. He handed me a phone. I never got a bill, even when I turned the clunky black phone back in. I now have a lifetime of Michigan-football stories, from historical moments spanning the globe—Angola’s civil war, Iran’s revolution, South Africa’s uprising, Qaddafi’s Libya.

The college-football season begins nationwide this week, after a strange one-off opener between California and Hawaii last weekend, in Sydney, Australia (where the game is known as “gridiron,” since football is a different sport). Nowhere is anticipation greater than in Ann Arbor—or Ann Arbaugh, as T-shirts now proclaim in deference to Jim Harbaugh, the most zealous coach in the country. Harbaugh has dazzled his way across the sports world since returning to his home town last year to revive a famed football program that had gone flat. He’s one of the few pro coaches to go back to college ball, despite having taken the San Francisco 49ers all the way to the Super Bowl, in 2013.* Harbaugh’s 49ers faced the Baltimore Ravens, who were coached by his slightly older brother John. Jim lost that sibling matchup, 34–31, and last year walked away from the pros, after splitting with the 49ers, to return to his alma mater.

Harbaugh is now shaking up college football with an “enthusiasm unknown to mankind,” which is his football mantra as well as the title of his new book, completed in collaboration with the Pulitzer Prize-winning war photographer David Turnley. Over the past year, as he has taken charge in Ann Arbor, Harbaugh’s zany zealotry has made him either beloved or loathed. He went to a high-school class with a recruit and even did a couple of sleepovers at recruits’ homes to convince them to sign with Michigan. He ran a blitz of one-day football camps across the country for high-school players, which Fox Sports reported “made Taylor Swift’s ‘1989 World Tour’ look like mere child’s play.” That project—hotly contested by other coaches as outside the rule book—included thirty-eight stops in twenty-one states and two other countries in less than a month. Over the past six weeks, a raucous video that Harbaugh recorded in the Michigan stadium, with Bailey, a San Francisco Bay Area rapper, has had almost a million views on YouTube. It’s titled “Who’s Got It Better Than Us?,” from a phrase coined by Harbaugh’s dad. In the opening shots, Harbaugh drives Bailey into the frenzied Michigan stadium in a maize Lamborghini—one of Michigan’s colors.

Along the way, Harbaugh has appeared twice with Michelle Obama—once at the White House, in the middle of last year’s football season—to promote her program to encourage higher education. The President dropped by to discuss the college season. The coach also went on an annual Catholic mission trip to a remote town in Peru. He played catch on a cobblestone street in Paris, an image of which was posted in one of his many offbeat tweets. (@CoachJim4UM has almost eight hundred thousand Twitter followers.) And he popped into the Supreme Court and met with five Justices—John Roberts, Anthony Kennedy, Ruth Bader Ginsburg, Elena Kagan, and Clarence Thomas. He signed a book for Kagan, got a selfie with Ginsburg—“very dynamic speaker,” he noted—and tried to convince Thomas, a notorious Nebraska fan, to adopt Michigan as his second-favorite team.

“The surreal off-season of Michigan’s new football coach has reached the point that there is no place on the planet where Harbaugh could show up and surprise anyone," the _Wall Street Journal _reported.

Last season, Harbaugh took an inherited team with a losing record and coached it to a 10–3 season and a bowl game. This season, he has his own freshman class, announced in a “Signing Day of the Stars” spectacular, in February, that brought in the Yankees’ Derek Jeter, the Patriots’ Tom Brady, and other national sports legends, just to welcome the recruits as they marched down the aisle in the cavernous Hill Auditorium. The show, which ran more than two hours, was streamed live to hundreds of thousands of viewers. College football had never seen anything like it. Whatever happens this season, he’s already become—in the words of the Michigan fight song—“a conquering hero.” He’s even redefined fashion in Ann Arbor, where khakis have made a comeback among fans at Michigan games; that’s the Harbaugh uniform.

Michigan football was fabled long before Harbaugh. HBO did its first college-football documentary, in 2007, on the rivalry between Michigan and Ohio State. The teams’ annual match, dating to 1897, pre-dates the existence of the National Football League by a quarter century and baseball’s World Series by six years. In 1950, fifty thousand fans turned out for the game as a blizzard dumped several feet of snow, turning the field into an ice rink and forcing forty-five punts—some on first downs, because it was too dicey to either run or pass. Michigan won 9–3—without ever getting a first down. In the seventies, the ferocious feud between the teams’ coaches—Michigan’s Bo Schembechler and Ohio State’s Woody Hayes—was dubbed the Ten-Year War, and it was the fiercest in football. Schembechler had been Hayes’s assistant coach; his subsequent defection to Michigan led students in Columbus to hang him in effigy before the big game.

It’s the entire Michigan-football experience that captivates, however. The Big House has always been the largest football venue for any team, college or pro, in the country. It holds more than a hundred and seven thousand people—twenty-five thousand more than the largest stadium for a pro team, the MetLife Stadium, shared by the Giants and the Jets in New York.

“When Michigan makes a big play, and a hundred thousand people stand up spontaneously, without being told, and ‘Hail to the Victors’ kicks in, it’s the biggest choir in America. It’s not a business, it’s a religion—and one where everyone is welcome,” John U. Bacon, the author of “Endzone: The Rise, Fall, and Return of Michigan Football,” told me. “The Dalai Lama and Mother Teresa have both noted that the great disease of Western civilization is loneliness. Yes, it’s possible to be lonely in a crowd—but not this one.”

This season, Alabama’s Crimson Tide is a favorite to win the national championship. But, earlier this summer, ABC reported that Las Vegas sports books had taken in more money on bets that Michigan would also make the national-championship game. Go, Blue!

*This sentence has been corrected to clarify that several pro coaches have gone back to college ball.