Gary Clark Jr. performs at the Austin City Limits Music Festival in Zilker Park on Friday, October 2, 2015. JAY JANNER / AMERICAN-STATESMAN

“My name is Gary Clark Jr., from right here in Austin, Texas,” the guitarist who’d just ground the HomeAway Stage at ACL Fest into splinters at sundown Friday proudly announced to a crowd that clearly carried the same pride in calling him their own.

This was a big moment for the blues-rock boundary-pusher, and he didn’t disappoint. Focusing on songs from his new top-10 album “The Story of Sonny Boy Slim,” Clark and his lean three-piece backing band drew a huge crowd to a stage that might not have been quite big enough for his audience. But with the sun setting behind him just as he launched into his 7 p.m. set, Clark struck a magical moment of sound and vision.

Between songs, he was grateful but not boastful. He greeted the crowd with simple shout-outs: “What’s up, Austin!” “How ya feelin’?” “All right, people!” And, late in the set, when the crowd spontaneously erupted into a chant of “Gary! Gary! Gary!” just before he broke into the new album highlight “Grinder,” he answered, “Wow: I love y’all,” without a hint of pretense.

Gary Clark Jr. at ACL Fest 2015. JAY JANNER / AMERICAN-STATESMAN

Near the end of his hourlong performance, Clark brought out his sisters Shawn and Savannah to sing on the gospel tune “Church,” explaining that it was something special he could do on this night in his hometown.

They stuck around for the obvious closer, the new record’s leadoff anthem “The Healing,” which highlighted the soulful passion of his voice in equal measure with the blazing revelations coming from his guitar. “It requires devotion, from those who truly believe,” he sang out to tens of thousands of true believers, indeed.