Looking out across the jam-packed floor and balconies of ACL live on Monday night, and knowing two more sold-out shows would follow on Tuesday and Wednesday, a natural question came to mind: How did Gary Clark Jr. do it?

The story of the native Austinite's rise from local clubs to international stardom has been well-documented, sparked in large part by an invitation to play Eric Clapton's Crossroads Guitar Festival in Chicago in 2010. But one interesting part of these ACL Live shows is observing, through the music Clark delivers onstage, what an intriguing coalition of fans he's built to sell 7,500 tickets across three nights.

• PHOTOS: A-List gallery from Gary Clark Jr. at ACL Live

Part of his base, for sure, are the guitar-hero worshipers who turn out en masse at ACL Live for events like next week's "Generation Axe" all-star bill. Song after song on Monday night, Clark unleashed uproarious, dominating solos; his playing remains at the center of his art.

But he's also clearly connected with the jam-band crowd that regularly packs this venue for the likes of Widespread Panic or the Tedeschi Trucks Band. Taking the stage at 9:27 p.m. on Monday, he'd gotten through just two songs by 9:45; another number ran nearly 15 minutes. Clark and his four-piece backing crew — keyboardist Jon Deas, guitarist King Zapata, bassist Johnny Bradley and drummer Johnny Radelat — are more than willing to stretch things out with heavy jams, deep grooves and showy solos. (When Clark remarked near the end of the night that "it smells good in here," the dots were pretty easy to connect.)

And then there's the new-Austin hip crowd, proud of the Live Music Capital's most prominent native-son musician. Clark's hometown shows are a big event, clearly, and a lot of folks want to be there just to take it all in.

Less of his following may be the old-Austin blues purists, though that's just a guess. Despite Clark's ownership interest in Antone's and his deep love for classic blues — the encore on this night included Albert Collins' "If Trouble Was Money" — most of his music pushes well beyond those boundaries. He's never been content to just be a younger Vaughan brother, and that's likely to become even more clear when his next album, "This Land," arrives on Warner Bros. early next year.

Clark dug into some of that new material on Monday night, though tellingly he held back the incendiary and politicized title track (which will probably get a big push after the new year). He worked in a few past favorites, too, including the soulful, falsetto-driven "Our Love" from 2015's "The Story of Sonny Boy Slim," before concluding the 90-minute main set with his blazing cover of the Beatles' "Come Together" recorded for the soundtrack of the 2017 DC Comics superhero film "Justice League."

Clark returned for a half-hour encore, highlighted by an all-hands-on-deck finale with local group the Peterson Brothers joining him onstage. Earlier, Glenn and Alex Peterson, joined by Clark keyboardist Deas and drummer Brannen Temple, had opened the show with a tone-setting 45-minute set that hit the high points of their repertoire, including the choreographed moves on "Lie to Me" and Alex's sweet violin instrumental take on "Amazing Grace."

Next Monday, they'll be back at the Continental Club, holding court for their weekly happy-hour residency there. But for one special Monday, they got to shine bright on the big stage with Clark, who's always been good about remembering his home folks. Wednesday's show will feature Clark's Austin High School classmate Eve Monsees and her band the Exiles, with Memphis guitar star Eric Gales opening Tuesday's show.