The younger Campolo found his way to religion in high school, when he fell in with some guys who were active in a Christian youth group. For a while, he was always with them but wasn’t yet one of them. Then one day, a member of the group took Bart out to breakfast at a McDonald’s in Wayne, Pa. “He said, ‘You’ve been hanging around us a long time, Bart,’ ” Campolo recalls. “And he said: ‘I don’t think you’ve ever really accepted Jesus as your personal lord and savior. So what about it?’ ” Sitting in a booth, Campolo bowed his head and recited a prayer accepting Jesus into his heart.

His faith had already begun to falter by the next summer, while he was working at a camp for poor children in Camden, N.J. Some of his campers had been sexually abused, yet his religion told him that a benevolent God controlled every last thing that happens on earth. He had a hard time squaring these two thoughts. Later, as a freshman at Haverford College, he had two gay roommates. At the time, even liberal evangelicals like his dad treated homosexual behavior as a sin, but Campolo couldn’t bring himself to think ill of his roommates. He instead adjusted his theology to make room for them. Campolo finished college at Brown and eventually moved to West Philadelphia, where he started a ministry.

At first, even as he began doing Christian field work, Campolo resisted his father’s vocation of big-time preaching. But when he had to raise money for his mission program, the best way he knew was to hit the Christian conference circuit. After all, as a boy, he’d watched his dad. He knew how it was done. And he did it nearly as well, with his own distinct style. Where Tony had a grounded, authoritative stillness in the pulpit, Bart was a more hyperactive speaker, caffeinated by Christ. He was funny, alive, hard to ignore. He connected, and soon he was touring the country preaching the Gospel. Campolo ran his mission, raised money on the road and, after his father had a stroke in 2002, spent one day a week helping him run his ministry.

The abstract, bureaucratic nature of the work wore him down, and in 2005 the family decided together to move to Cincinnati, where some friends had already settled. Campolo, his wife and his two children moved into a ramshackle house with no real appliances, just a space heater and a hot plate. By day, Campolo was still traveling and working for his father remotely. In the evenings, he and Marty began hosting dinners for people they met in the neighborhood. Their informal fellowship soon included junkies, ex-cons, welfare moms and other neighborhood folk. These new friends helped him realize that the work of a minister is often not to save people, as so many evangelicals try to do, or even to change them, but just to love them unconditionally. He remembers one guy in particular, a toothless addict who had been in and out of jail his whole life. “You’re not going to fix him,” Campolo says. But by giving the man a community, Campolo told me, you can give his life some meaning. And maybe that’s enough.

At U.S.C., Campolo’s Secular Student Fellowship now comprises between 75 and 100 students, although not all come to every meeting. Last year I attended one of their dinners, in a nondescript meeting room in the chaplain’s building: folding tables, metal chairs, industrial carpet, the whole institutional works. Roughly 25 students were there, most of them pleasantly nerdy and inquisitive. Several told me they were lapsed Christians who were afraid to come out to their parents. After they had all filled their plates with the chili that Campolo and his wife cooked, Campolo began to talk. He did his best to stay seated on his stackable metal chair, but when he made a particularly emphatic point, he bounced to his feet, like the preacher he used to be.

The topic was friendship, and Campolo’s text was “The Friendship Factor,” Alan Loy McGinnis’s 1979 megaselling self-help book. There was a reason he turned to it. When Campolo arrived on the U.S.C. campus, in the fall of 2014, he quickly discovered that the fundamental problem of many students was loneliness. He hypothesizes that their focus as high-school students on résumé-building and test-taking, so crucial to getting into college now, has left many of them socially adrift once they arrive. “Kids who show up at college on the other end of that rat race are very good at networking,” he says. “But they are not always very good at deeper connections.” The grown-ups in their lives are also primarily focused on achievement and rarely steer them toward the important questions.

Campolo told me that when students come to talk about a job they’ve been offered, he asks questions like: “What’s the culture like at that place? The guy who interviewed you — would you want to end up like him, with the kind of marriage he has and the kind of friendships he has?” Campolo went on: “And they say, ‘Huh, I never thought about that.’ And you want to say: ‘Where are your parents? Or your pastor? What is your Uncle Joe doing? Why is nobody asking value-oriented questions about your life?’ ”