Throughout his lengthy career Keller Williams has proven to be prolific and musically fearless—a singer-songwriter constantly evolving how his songs are presented. Starting as an acoustic troubadour more than two decades ago, Williams has consistently tested the limits of what a single musician should be able to do, and at the same time he’s juggled fronting a variety of bands that cover a wide range of genres, from funk to reggae to bluegrass. Late last month the Fredericksburg, Va.,-based, multi-faceted tunesmith released two new albums, Raw and Sync, his 21st and 22nd overall efforts, that showcase both his solo and collaborative sides.

Williams emerged in the latter part of the 90s, a shaggy troubadour fresh off a Grateful Dead tour with fast hands on his six- and 12-string axes and a notebook full of quirky tunes. In a then-flourishing jam band scene long on psychedelic solos but short on lyrical enlightenment, Williams turned heads with his engaging chill-dude anthems—crafted not in the poetic style of Robert Hunter, but more like an observant, goofy comedy writer, documenting the mundane around him, creatively not taking himself too seriously.

He started building a loyal fan base as a dynamic solo act. At first he just relied on his nimble-fingered, percussive guitar work, which he’s declared was developed based on the style of late new age folk hero Michael Hedges, who died in a car accident in 1997. But as the years went on, Williams started adding toys to his sonic arsenal—hand drums, bass and additional strings, even plastic tubes—and expanding his acoustic-based songs through on-the-spot, live digital looping.

Raw takes Williams back to the sound of his early days—just guitar and voice—before he became a one-man band blending strings and tech-savvy tricks into his self-dubbed “acoustic dance music.” Williams was inspired to make the stripped-down record after playing some split-bill shows with idiosyncratic finger-picking wiz Leo Kottke, who gets a direct shout-out through the inventive instrumental “Thanks Leo.”

While, overall, Raw has a primitive feel, like a collection of demos, it offers an entertaining sketch of Williams’ versatility. Another wordless offering, “Ticks Be Told,” is more relaxing than the aforementioned Kottke homage. Williams also showcases blues basics to declare he won’t be denied a good night of dancing in “Right Here,” and comical speed-folk is used to recount the tale of Kings of Leon quickly ending a concert after being showered with pigeon poop in “Short Show.” The album’s lone cover, “Return to the Moon,” strips indie rock duo EL VY’s electro-pop cruiser down to its tuneful core.

Williams can certainly harness the value of barstool heart, but he’s also never been one to shy away from playing with others. He spent a long stretch of time regularly opening for veteran jam outfit the String Cheese Incident, who backed Williams on his 1999 album Breathe. In 2007 he enlisted a cast of his favorite musicians, including banjo master Bela Fleck, conscious hip-hop MC Michael Franti, and Grateful Dead singer and guitarist Bob Weir, to assist with his ambitious, if a bit disjointed, guest-filled effort, Dream. Currently Williams shuffles his touring schedule between solo gigs and fronting a variety of different side bands. He often gigs with his hard-hitting funk crew, More Than a Little, or in projects with bluegrass greats, including Larry Keel, the Travelin’ McCourys, and the Infamous Stringdusters.

In Sync, Williams showcases yet another band, KWahtro, a jazz-minded acoustic quartet featuring a line-up of seasoned pros: Veteran guitarist Gibb Droll, who’s played lead for Bruce Hornsby and Marc Broussard, versatile drummer Rodney Holmes, best known for his work with Santana, and go-to New York City bass ace Danton Boller. The group places Williams’ songs in the realm of airy fusion rock—propelled by tight grooves that also leave room for wide-open solos and on-a-dime time signature shifts. The songwriter’s sense of humor is intact in the Bebop-driven “Missing Remote” and the colorful hip hop-hued funk jam “Watchoowantgurl.” The equally hashtag-ready “Hategreedlove” delivers a more seriously toned unifying message within its Afro-rock bounce.

Sync closes with the quartet burning through “Running on Fumes,” a tune Williams recorded all by his lonesome on his third record, 1998’s Spun. It starts as a silly song about being a musician on the road, beginning with the line, “More than often I drive so much, it’s like my ass is my feet,” and featuring Williams waxing poetic about Mountain Dew and Waffle House stops as ways to stay awake at the wheel. But as the song progresses he gets more contemplative, singing: “I love it when it all runs together/ You gotta think about where you’ve been/All of the places and the weird looking faces/I love it when it never ends.”

Even with a free-flowing mind, Williams knows when it’s time to ride alone and when it’s best to play with friends.

Keller Williams is covering a lot of ground throughout the Southeast and Mid-Atlantic regions this winter and spring. He’ll team with up Leo Kottke for a series of Shut the Folk Up and Listen duo shows at the Carolina Theatre in Durham, N.C., on February 16, the Carolina Theatre in Greensboro, N.C., on February 17, the Lincoln Theatre in Washington, D.C., on February 18, and the Variety Playhouse in Atlanta, Ga., on April 7. He’s playing solo shows at the Bright Box in Winchester, Va., on March 3 and at the Harvester Performance Center in Rocky Mount, Va., on March 4. He’ll also bring new band KWahtro to the VA Beach Funk Out in Virginia Beach, Va., on May 20.