After Hurricane Katrina hit, Rick Warren was one busy pastor. He traveled to Houston to preach to 8,000 evacuees in the Astrodome, standing in a skybox next to Oprah Winfrey. He went on the Larry King show to explain how churches were stepping in to do relief work. He lobbied his friends in the White House to release disaster-aid money to religious groups. And in case anybody missed his post-hurricane tour, his publicist issued a press release when it was done.

In part by campaigning for the job, Warren, the 51-year-old Southern California pastor, bestselling author, and management genius, has become secular America's favorite evangelical Christian. This year he has spoken at Harvard, Oxford, Cambridge, the Aspen Ideas Festival, the Young Presidents Organization, a Pew Foundation forum for religion writers, and the University of Judaism. (The rabbis wanted to get his advice on how to increase their market share.) He has gone before the Council on Foreign Relations to pitch his newest idea: a breathtakingly ambitious project to mobilize American Christians to fight poverty, illiteracy, and AIDS in Africa.

A protégé of management thinker Peter Drucker, Warren is also cultivating corporate executives. He calls himself Rupert Murdoch's pastor, he has entertained Jack Welch at his home, and he will meet Bill Gates at a Time magazine conference on global health, where they are both scheduled to speak. He also has forged ties with celebrity activists like Bono, who arranged to make him official pastor of the Live 8 concert last summer in Philadelphia. ("The only thing I remember about that concert is Linkin Park and a sweet smell in the air," Warren joked to his congregation.) If a middle-aged Baptist minister can be said to possess that elusive quality called buzz, Rick Warren has it right now.

Several factors explain why. One is the clout of evangelical Christians. They now number some 30 million to 50 million Americans, and their overwhelming support for George W. Bush, a fellow evangelical, helped him win reelection last year. (Warren sent a letter to 150,000 pastors, in effect urging "those of us who accept the Bible as God's word" to get out the vote for Bush.) Harriet Miers, Bush's embattled nominee for the U.S. Supreme Court, will be the first evangelical Christian to sit on the court if she is confirmed. Warren emerged from the pack of evangelical leaders because his book, The Purpose-Driven Life, has sold 26 million copies since it was published by Zondervan, a unit of Murdoch's News Corp., in 2002—making it one of the decade's top sellers, up there with The Da Vinci Code. He has also set himself apart by putting a friendly face on a movement that scares a lot of people with its positions on issues like abortion and gay rights. Warren shares those absolutist positions—he believes homosexuality is a sin and Jews will go to hell—but doesn't emphasize them. (For more on the culture wars, see the following story.)

Most of all, Warren gets attention because he is, as he likes to say, a "spiritual entrepreneur." Using techniques that he learned from Drucker, among others, Warren built Saddleback Valley Community Church in Lake Forest, Calif., into one of America's biggest religious institutions. "Forget any opinions you have about religion and just look at the guy as a CEO, and you've got to be impressed," says Joe Ritchie, a Chicago businessman and Warren ally who once ran the world's largest options-trading company. Today Saddleback has an annual budget of $30 million, 300 employees, a 120-acre campus, and around 22,000 worshippers each weekend. Warren also founded Purpose-Driven Ministries, a nonprofit network of about 150,000 pastors, which has its own staff of about 180 people, a $39 million budget, and a thriving website called pastors.com. Its members may be Baptist or Methodist or Episcopalian, but they use his system. Call it open-source evangelism. "We're kind of the Linux of Christianity," Warren says.

Warren is a new brand of evangelical leader—an affable baby-boomer who is savvy about business, comfortable in the mainstream culture, and eager to build coalitions around his major concerns. Because he would like hard-line churches to play an even bigger role in national and global affairs, he wants to soften the image of evangelical Christianity—which leaves him open to the charge that he is trying to have it both ways. He says he's not interested in politics, but he stepped into the culture wars to help the President. He talks about the sin of pride, but basks in the spotlight. And his ambitions are so vast that they practically invite scorn—uniting liberal and conservative Protestants, fixing Africa, transforming the very nature of American culture. "We have a goal to move Christianity in America from self-centeredness to unselfishness," he says. Now, as this purpose-driven pastor steps onto the national stage, he faces new questions: What will he do with his influence? Can he turn evangelicalism in a new direction? Will success spoil Rick Warren?