A debut album that goes No. 1 and sells more than 15 million copies; a Grammy Award for best new artist; performances at Farm Aid, the World Series and Frank Sinatra’s 80th birthday bash; Garth Brooks turns down an American Music Award, saying four guys from South Carolina deserved it over him; six hit singles, and another No. 1 album that sells 2 million.

What else could possibly be left for Hootie & the Blowfish?

Plenty, say guitarist Mark Bryan and bassist Dean Felber.

“That all makes dreams come true,” Felber said recently, “but it doesn’t make a career come true. We still have dreams, but the dreams weren’t anything on that list, really. We’ve accomplished individual dreams through what we’ve done, but our dreams together have nothing to do with any of those. Longevity is what matters, to be a band that makes total albums and complete albums for 10, 20 years.”

The band has crafted its most complete album to date, “Musical Chairs,” its third for Atlantic. Out Sept. 15, the album finds Bryan, Felber, lead singer-guitarist Darius Rucker and drummer Jim “Soni” Sonefeld marching to its familiar Hootie beat but also slightly stretching pop’s boundaries with forays into country, bluegrass and even R.E.M.-ish alternative rock.

“We have to grow as people and as musicians in order to keep it fresh,” Bryan said. “I have to admit, this one was probably the most difficult to write, because we know we have a standard for ourselves, regardless of the fans or the press.

” ‘Hey, we did this with the first record, as far as what it sounds like and what the songs were; the second record has its direction.’ The third album, we knew we wanted to sort of outdo ourselves. We spent several months together writing songs and throwing stuff out, revisiting ideas over and over again. Because we took several months off before we were writing, it was difficult to get back together and all be on the same page. It was an experience writing this record. We learned a lot, what to do and what not to do.”

What they didn’t do was rest on their laurels. After extensive writing sessions last fall at a retreat in Jackson Hole, Wyo., and later in Phoenix, they road-tested their new material in a series of Northeast club dates. From there, they whittled down their wish list of tracks to 13, including a hidden CD track.

“The songs weren’t eliminated from crowd response or anything like that,” Felber said. “It’s just that they got beaten out by other songs. When you write 30 songs, they all start at the same spot. People have their favorites and stuff, then each time some of them jump out, then it’s down to 20, then 15, and that’s what you end up with. When we took them on the road, most of the songs were in transition and some of them just didn’t make the transition.”

“Whatever direction a song came in, we weren’t scared to keep it there,” Bryan said. “In the past, we sort of veered a song toward the mainstream Hootie sound, just because that’s all we knew. But now everybody’s more comfortable with their playing and comfortable with different styles that we can play a bluegrass song or keep a song hard-rockin’, wherever it’s supposed to sit.”

Many of the songs, notably “Only Lonely,” “One By One” and the first single “I Will Wait,” offer a paean to lost loves, strained relationships and separation. Bryan said there wasn’t a conscious stream connecting all the songs on “Musical Chairs,” but he thinks listeners will detect a theme anyway.

“We never sit down and say, ‘This record’s going to be about unrequited love,’ or whatever,” he said. “There probably is a theme to this record, as we look back at it, but you have to remember, our four lives are parallel. When we’re off, we’re all four off; when we’re on, we’re all four on. If we’re in Asia, we’re all four in Asia. Our personal lives are different, but our lives are pretty parallel, so there’s a chance we’re all going to write about the same stuff, just from different perspectives.”

Each band member had a hand in the songwriting, which dispels any notions that Rucker is running the show.

“It’s weird, after every album, people ask, ‘Was he thinking this, was he thinking that?’ ” Felber said, “but everybody writes in this band. There’s songs where Mark and Soni will have passages of lyrics that once Darius sings them, people automatically think it’s his thoughts. It’s weird how people can get one train of thought through a whole album and there’s like four different people speaking on the album.”

“Musical Chairs” is likely to become Hootie’s third straight No. 1 album, and to think just five years ago, they were struggling in their native Columbia.

“It was hard just to get ‘Kootchypop’ (EP) on the local radio station,” Felber said. “That took years of us calling even before ‘Kootchypop’ came out and then once Rusty (Harmon) became our manager and him taking the reins on that and calling the same radio stations, then they started playing it and people started calling. It was such a long process that we never thought it could happen nationwide. We thought it would take state by state 10 years for that to happen.”

“I can remember not being desperate but just wondering if it was going to happen and wondering what is ‘it’ if it does happen,” Bryan said. “We just knew we had to keep playing and keep enjoying ourselves.

“We were just happy for ‘Cracked Rear View’ to sell 200,000 copies. That was a huge number for us. But then to turn around and for it to sell 15 million, nobody could ever predict that. Anybody that says they expect to sell 15 million is lying, because if you know that then you know the secret to the pop industry, you know what people in America are going to buy, and nobody can guess that.”

Their career has only just begun, Bryan said.

“With this new album, we’re definitely taking the road less traveled, the harder road, and not by choice,” he said, “but I think we’re worthy of the challenge. I honestly think ‘Musical Chairs’ is better than ‘Cracked Rear View.’ I’m confident that, say, if we only had sold five copies of ‘Cracked Rear View,’ I really think we’ve grown to the point where, ‘Wow, hey, we’re actually a better band.’ ”

ON THE WEB: www.hootie.com.