"I stole my entire catalog from Guns N' Roses and Motley Crue. I just loved the music and wanted to learn to play their songs," said Levine, who also has a major jones for Led Zeppelin and The Beatles. "I've been a metal-head from the age of 10 until now."
Levine, who jammed with Wonder at last year's Live 8 concert and has sung on records by Kanye West and Alicia Keys, is still a metal-head?
"Of course," he said, speaking from a recent tour stop in South Carolina. "Our shows are a lot louder and ruder than people know, unless they go see us. There's a lot of guitar solos and jamming out."
In fact, previous Maroon 5 tours have found the five-man band belting out lively versions of AC/DC's "Highway to Hell" and Neil Young's "Rockin' in the Free World."
As if to reinforce these hard-rocking tendencies, one of the opening acts on the band's current tour is The Hives, the raucous Swedish garage-rock revival band. The other is Phantom Planet, a Los Angeles garage-rock revival band now seeking to broaden its musical horizons in its post-Jason Schwartzman incarnation.
On the tour, Maroon 5 will mix songs from its chart-topping new album, "It Won't Be Soon Before Long," with favorites from its 2002 breakthrough, "Songs About Jane." The five-man band's debut release, the Grammy Award-winning "Jane" has sold 4 million copies in the United States and another 6 million around the world, where it topped (or nearly topped) the charts in 35 countries.
But even with some loud jams and rude guitar solos to spice up its shows - along with Levine's solo acoustic version of Guns N' Roses' "Patience" - Maroon 5 isn't about to leave its polished, radio-friendly blend of pop, rock and R&B behind.
The band owes its success to "She Will Be Loved," "Sunday Morning," "This Love," "Makes Me Wonder" and other hit songs that blend pop smarts and blue-eyed soul into a winning formula. Never mind that Levine maintains he gives little forethought to how his band's songs will sound:
"I'm not a very specific thinker when it comes to the music.
"There's no rhyme or reason to why certain decisions are made. We just do what feels right. Naturally, that I just like to ramp up the energy in a chorus; it makes it shine."
What Levine and his bandmates are specific about is that they must believe in their songs from start to finish, and that they not let their enthusiasm lag.
"The momentum of what you're doing is really important," he said. "You need to love it throughout the entire process, even if it's driving you crazy. You have to think 'I'll get to the end of this, and it will be a great finished product.'
"If you lose faith in it, it dies. At the end of the day, you need to be in love with it. Otherwise, it will be mediocre - and it will show in the music."
More than many bands, Maroon 5 proudly wears its influences on its sleeve.
On its new album, the song "Not Falling Apart" suggests that the group - which also features guitarist James Valentine, vegan bassist Mickey Madden, jazz-inspired keyboardist Jesse Carmichael and ex-Gavin DeGraw/B-52s drummer Matt Flynn - are all fans of The Police's landmark 1983 album "Synchronicity."
Another new number, "Little of Your Time," pays homage to both Prince and Hall & Oates, while Levine credits Herbie Hancock's classic 1973 jazz-funk album "Headhunters" for the percussive textures featured on several songs. The trick for Maroon 5, as for any still-developing young act, is to display reverence to their influences while adding to - rather than merely mimicking - their work.
"I think we're definitely doing a little of both on this album," Levine said. "But at the end of the day, it's best to blur the lines of when that's happening and not have such a specific moment. We're not perfect and we sometimes take liberties and go a little too far. But we also have our own sound that pokes through."
That sound has brought Maroon 5 two Grammy Awards (one in 2005 and another last year), made its members rich and earned them recent praise from Rolling Stone and Billboard. But it has also made the band the subjects of some less-than-flattering reviews.
The indie-rock-championing Web site Pitchforkmedia predicted Maroon 5's fall tour will "smother North America in a downy pillow of soft rock," while the Village Voice dismissed the band's new album as being "clearly designed solely for 14-year-old girls." Levin, not surprisingly, bristles at his detractors.
"I'm a human being - it hurts," he said. "But I've got the world on my side and a couple of ... (insert word that sounds a lot like 'glass pole') critics who have decided not to like us.
"I think longevity is important, because I want to show people. I don't know if we'll break up in a year or not, but the longer you stick around, the more people respect you for not being a flash-in-the-pan. And I know we're good enough to stick around as long as we want."