He plays folk, country and rock and lately has delved into rhythm and blues, with his new album called "Funk."
Williams fell into the sound when his friend, drummer Toby Fairchild, invited him to a nightclub show.
"He was performing an R&B night at a local bar and had asked a random cast of musicians to play," Williams said during a phone call with The Park Record from Keystone, Colo. "On this particular Tuesday night, the band was incredible. I remember it being so real, so improvisational and awesome. So I filed that away in my back pocket and saved the idea for myself until the time was right."
That time came in the fall of 2012.
"I always put together projects that allow me to play every year between Dec. 26 through Dec. 31," Williams said. "So I got this band together, which was essentially the same band that played that one Tuesday night."
Williams and the musicians practiced every Tuesday from September to December and played six shows.
"We recorded everything, and that's where 'Funk' came from," he said. "It's a live documentation of the shows.
"I've always been into the classic band setup with keyboards, guitars, drums, bass and female backup singers," Williams said. "I really wanted to go into this."
The vibe felt so good that 14 months later, he still tours with the band on occasion.
"That also gave me an excuse to give me the opportunity to promote a record, which I usually don't do," Williams said. "So any excuse that gets my wife to allow me to get on a bus and tour with these people is OK by me."
When the musician comes to Park City this weekend, he will perform his solo show, which is OK with him, because he will play some stripped-down versions of the "Funk" tunes.
"All the songs on the album originally started as acoustic tunes and I adapted them to the funk style," Williams said. "I would teach the songs to the band and they would teach them back to me in this gospel, R&B, soul formula, which I wasn't really used to.
"As soon as write songs, I would play them live, because I could never wait to play new material," he said. "So, I'll be playing them in their original forms, so to speak."
Playing in the band has helped Williams with his solo performances.
"Each element helps the other in the sense that playing solo so much makes me want to play with the band and vice versa," he said. "With the band, we put in new songs into the set every day, and with the solo shows, my repertoire is so vast that there is so much to choose from."
Sometimes having a large catalog of songs proves challenging when it comes to creating a set list.
"I wish I didn't have to spend as much time on a set list as I do," Williams said, laughing. "I'm a little weird that way because I keep track of everything. I pull up set lists of the past times I'm in places and try not to play the same songs."
When he plays with the band, Williams feels like he has to play at least some of the same songs every night.
"But when I'm solo, I use the process of elimination to decide which songs I will play," he said. "I will look at the sets and try to play completely different shows.
"It would be so easy to get into a rhythm and play the same songs every night, but I try to get to that point," he said.
Since Williams has a plethora of tunes to choose from, he has slacked off on songwriting.
"It goes a lot slower these days, and many ideas get ditched," he confessed. "I maybe write four songs a year. The songs are mainly about things that have made me laugh."
The last song he wrote is called "She Rolls," which was done in the Danny Barnes school of songwriting, Williams said.
"The idea is to make up a character and take it on an adventure," he said. "When I wrote it, it as a chicken-picking country tune that I shopped to Toby Keith and Big & Rich, but I never heard anything back. So, I'm playing it live and it sounds so different than the demo."
Since Williams isn't as prolific as he has been in the past, he enjoys recording cover songs.
Some of the covers on "Funk" include the Talking Heads' "Once In a Lifetime" and the Grateful Dead's "West L.A. Fadeaway."
"The covers, unfortunately, choose me," he said. "They creep into my brain and I have to learn to play them to get them out of my head.'
Another Grateful Dead tune, "Samson and Delilah," found its way into the album's track list.
"That song totally got turned over into a hungover gospel take that we call 'Samson's Wine,'" Williams said.
When the funk fizzles out, Williams said he has some new ideas he would like to explore.
"I'm still toying with the idea of acoustic dance music, which many people have laughed off as a silly notion," he said. "But I would like to go the EDM (electronic dance music) route build the tension and drop the explosion all with acoustic instruments.
"I haven't been able to get anyone on board with that, yet, but that's my idea," he said.
Keller Williams will perform at Park City Live on Friday, Feb. 7. Doors open at 8 p.m. Tickets range from $20 to $30 and available by visiting parkcitylive.net.