Being in a rock band on the road is almost a continuation of childhood for the three Followill brothers in Kings of Leon.

As boys they often slept in the car as their Pentecostal preacher father took his family from town to town.

"If we were in between cities and didn't have money to get a hotel, we'd just stop in a rest area or something," says Nathan Followill, 29, the drummer and oldest member of the Kings of Leon. "To us it seemed normal, because it was the only life we knew."

The Kings — Nathan; brother and lead singer Caleb, 27; youngest brother Jared, 22, on bass; and cousin Matthew, 24, on lead guitar — are still on an improbable journey, from itinerant preacher's sons to arena-filling rock band touted as the next great thing.

"The life we lived then is similar to the one we live now," Nathan says. "Except for the accommodations are a lot nicer and the beer isn't nonalcoholic."

If there are apocalyptic echoes "hot as a fever, rattling bones" in "Sex on Fire," the hit song from the Kings' fourth album, 2008's "Only By The Night," the salvation it talks about, "all the commotion ... feels like the greatest," is definitely earthly.

"Sex on Fire" lit the Kings on fire, spending eight weeks atop Billboard's Modern Rock Radio chart in 2008, earning a Grammy for best rock performance by a duo or group, and helping send the sales of "Night" to almost four million worldwide.

For the most part there's no trace of their religious background, except for their biblical-sounding first names. And, perhaps, the intensity with which they approach their music.

"Being a preacher, you're putting on a show," Nathan says. "You're up there to entertain and take people's minds off everyday problems."

The brothers were in their teens when their father began drinking and behaving erratically (he once tried to arrest a policeman for speeding). Their mother divorced him and took the boys to Nashville, where they got their first taste of previously prohibited rock music and pop culture.

"When my parents separated, the little glass castles of the world we thought were perfect came crashing down," Nathan says. "It was a point when we stepped back and looked at the lives we'd lived up till then and the lives we wanted to live."

They quickly decided the life they wanted was in a band. "We met guys who got paid to write horrible lousy country songs, and we were like, 'We could write lousy country songs,' " Nathan says. He had played drums at church services, and Caleb used to sing, but they were teenage amateurs when they auditioned for Ken Levitan, president of Nashville's Vector Management, whose clients include Emmy Lou Harris and Kid Rock.

"They had this amazing sound just singing a cappella," says Levitan, who became the Kings' manager. "This unbelievable sibling harmony. Caleb had a really unique voice. They came across as really confident. I think they were still trying to figure out what they wanted to be, but you could tell they loved music and this was something they wanted to do."

Levitan got the duo signed to RCA. But instead of hiring a backing band, the older Followill brothers decided to bring in Jared, then 14, and teach him to play bass, and cousin Matthew, 15, who played some guitar. "They were like, 'Cool, see you in a month, good luck with that,' " Nathan says. They shut themselves up in their garage, and about six weeks later, played a handful of songs, including "Holy Roller Novocaine" (about a preacher who seduces young women) for Levitan and some astonished label executives.

The Kings' first three albums, 2003's "Youth and Young Manhood," 2005's "Aha Shake Heartbreak," and "Because of the Times," from 2007, sold respectably but not hugely.

The group toured incessantly, and opened for U2, Pearl Jam and Bob Dylan, honing their musicianship and their ambition. "You're like 'Oh wow this is amazing,' " says Nathan. "On the other side we were picking their brains, 'How do you keep your sanity?' We want to be up there rocking 25 years from now."