By Scott McLennan

The guitarist led his razor-sharp band through two sets steeped in bluegrass that, at any given moment, could erupt into psychedelic jams, old-school country, metallic thrashing, or jazzy forays.

Billy Strings at the Leader Bank Pavilion, Boston, on July 25.

Billy Strings at the Leader Bank Pavilion. Photo: Sam McLennan

Billy Strings is headlining the final day of the upcoming 2023 Newport Folk Festival, an acknowledgment of his deservedly lofty place in the firmament of the modern Americana music scene. But Strings’s concert at the Leader Bank Pavilion in Boston felt as if it were a festival unto itself: the guitarist led his razor-sharp band through two sets steeped in bluegrass that, at any given moment, could erupt into psychedelic jams, old-school country, metallic thrashing, or jazzy forays.

Strings’s growing popularity merited two shows at the Pavilion, which followed a pair in Vermont and preceded a pair in Maine, all on the road to Newport. This was unusual — artists headlining festivals won’t play anywhere near that event in the days leading up to it.

But the following for Strings has become rabid, the result of how the 30-year-old guitar phenom built grassroots buzz through relentless touring. During the pandemic shutdown he stayed connected to his growing audience via a series of livestreamed concerts. Once people were let back into the venues, the flood gates of demand opened whenever Strings’s dates were announced.

In the Boston area, Strings and his band have steadily marched from the Sinclair through the Wang, christened the opening of Roadrunner, and are now doing multiple nights in Beantown’s 5,000-seat outdoor pavilion.

Royal Masat and Billy Strings at the Leader Bank Pavilion. Photo: Sam McLennan

Since his appearance at Roadrunner in the spring of 2022, Strings has added fiddle player Alex Hargreaves to an already-stacked lineup consisting of bass player Royal Masat, banjo player Billy Failing, and mandolin player Jarrod Walker. Hargreaves adds yet another layer of exquisite craftsmanship to this band’s sound, whose ensemble playing is nothing if not well-balanced, solos and intermittent face-offs between two or three players introduced while others hold down a groove.

Strings, though, is the undisputed gravitational center of the experience. That being said, he is also manages to be all over the place, literally and figuratively. Over the course of two generous sets, Strings danced, pranced, and whipped his long hair in circles worthy of the best death-metal guitar thrashers. All the while the musician never lost his preternatural command over the acoustic guitar: the instrument seemed to be an extension of his body as he produced wildly complex pieces of music, delivered with exhilarating ease at a furious pace.

Alex Hargreaves at the Leader Bank Pavilion. Photo: Sam McLennan

Strings initially hit the scene as a mind-blowing guitarist and an ever-improving songwriter. At this point has become adept at crafting a dynamic performance, one that intentionally (and comfortably) embraces a wide range of emotions, topics, and perspectives. Sometimes we’re digging back into the roots of bluegrass (“Katy Daly”); sometimes we’re pitching forward in a critique of modern folly (“Long Forgotten Dream”). Sometimes we’re wildly joyous (“On the Line”); sometimes we’re just beat down (“This Old World”).

Billy Strings and band at the Leader Bank Pavilion. Photo: Sam McLennan

The band played 21 songs, each hitting the mark in its own way. Here are a few standouts:

• The band opened the show with “Big Ball in Boston,” which has become something of an anthem whenever Strings comes to town.

• Bassist Masat makes much of the wild musical maneuvering possible. His skill and temperament are key to the band’s progressive style, which was proven many times on July 25th, as when his rhythm work steered the rustic “Salty Sheep” instrumental into the harder edge of “Heartbeat of America.”

• The highlight of the concert was a pairing of Eddie Noack’s truly unhinged country number “Psycho” with a blowout version of Strings’s own “Meet Me at the Creek,” during which everyone delivered fierce solos and the bandleader seemed in the grips of an ayahuasca trance as the song reached a near-breaking point before settling back down.

• Strings brought out young award-winning banjo player Victor Furtado for a few numbers, starting with a medley of “John Hardy” and “Gold Rush” performed as a duo, then “I’ll Go Stepping Too” and “Roll On Buddy, Roll On” done with the whole band for full hoedown effect.

• Strings’s recent collaboration with Willie Nelson has produced a fine song in “California Sober,” proof that not all new country music is trash.

• Strings’s plunge into abstract improvisation on John Hartford’s weird-to-begin-with “All Fall Down” was a daring move, challenging listeners to follow along a path shaped more by the influence of John Coltrane than of Phish.

• It was very late in the show before I realized, “Gee, Jarrod Walker hasn’t gone too wild tonight.” Then came “West Dakota Rose,” a sprawling, energetic instrumental that relied on discipline and structure. It was in direct contrast with the chaotic approach applied to the previous tune, “All Fall Down.” Walker’s masterfully imaginative mandolin work guided the rest of the players.

• Strings didn’t bother with the showbiz trope of leaving the stage and returning for an encore. Instead, the band did not waste a minute in delivering beautiful versions of “Secrets” and “Away From the Mire,” homey conclusions to this musical odyssey.

Scott McLennan covered music for the Worcester Telegram & Gazette from 1993 to 2008. He then contributed music reviews and features to the Boston Globe, Providence Journal, Portland Press Herald, and WGBH, as well as to the Arts Fuse. He also operated the NE Metal blog to provide in-depth coverage of the region’s heavy metal scene.