Big Sam Williams' size moved him to put down the basketball and pick up the trombone.

When Williams was 15 years old, he weighed 225 pounds and was deemed too big to take the court with his peers. He was told he would have to play with older kids, a prospect he didn't relish.

"I needed something to do with my time so I joined the marching band," Williams says during a telephone interview from his New Orleans home.

The band director asked him what he wanted to play and Williams asked what needed to be played. The director handed Williams a trombone, an instrument the teenager decided he could handle.

Thirteen years later, Williams, who was hired right out of high school by the Dirty Dozen Brass Band, a New Orleans musical institution, now fronts his own band, Big Sam's Funky Nation. The five-piece band, which recently released its fourth CD, "King of the Party," will perform in Lancaster city Sunday at the Marion Court Room. Also on the bill is Lancaster band D.C. & Co.

Williams, who does not come from a musical family and who first touched an instrument when he joined the marching band, says his mom showed him the path to a career when she bought him an album by the Dirty Dozen Brass Band.

"That album just changed my life," he says. "I told my mom, 'Someday, I'm going to be in that band or start one just like it.' "

He attended New Orleans Center for Creative Arts, which also claims trumpeters Terence Blanchard, Nicholas Payton and Wynton Marsalis as alumni.

Upon graduation, Williams took a job at a New Orleans theme park called Jazzland. He then got the call from the Dirty Dozen Brass Band.

"I love those cats," Williams, 28, says. "They showed me the way."

Williams, however, also wanted to branch out on his own and started the Funky Nation as a side project. He realized in 2004 that he was going to have to make a choice between the two bands.

"You can't ride two horses at the same time," Williams says. "That was a hard decision because I was making a lot of money and I loved that group. They were like my musical icons but I had to step out on my own and do it. It paid off. It was a hard decision but it paid off."

Big Sam's Funky Nation, which tours all over the world, plays about 275 gigs a year.

Williams also performed on the terrific album "The River in Reverse" by New Orleans legend Allen Toussaint and Elvis Costello.

"They called me for the album," Williams says, "and I was, like, 'Allen Toussaint and Elvis Costello?' "Are you serious? I didn't ask anything. I just said, 'You let me know when and where I should be, and I'll be there.' "

Williams also has a recurring role in the HBO television series, "Treme," a show based in post-Katrina New Orleans.

"That show is telling you the God's honest truth about exactly how things are in New Orleans," he says.

Williams is evidence enough that music continues to thrive in the Crescent City.

He says, however, that his nickname doesn't fit him quite as well as it did when he was 15.

"I've lost a lot of weight so people are trying not to call me Big Sam anymore, but I can't be anything else," Williams says with a laugh.

New Orleans Funk Concert/Party

Big Sam's Funky Nation

D.C. & Co. Sun. 2-6 p.m.

$10 advance, $15 at gate

Courtyard of Marion Court Room

37 E. Orange St. 509-1818
www.marioncourtroom.com