Austin alt-country heartthrob Shakey Graves has star power. He proved it Sunday on the Barton Springs stage with a fearless set and an adored catalog. As pop giants like Camilla Cabello played across the park, the songwriter born Alejandro Rose-Garcia tamed a sprawling horde just across the street.

It’s an unenviable position: Why see a big Austinite when he theoretically performs in town often? Well, for starters, Rose-García has blossomed into one of the area’s premier songwriters.

He began solo Sunday night, with a guitar and a white T-shirt. The longtime mainstay who’s strummed in town since a mid-2000s guest role on “Friday Night Lights” leaned on his stretched, sorrowful voice to rope folks in. A few songs later, a three-piece backing band fleshed out his cowboy-hat adorned, ramblin’ man antics.

The loud indie rock that came next won on its Lone Star-soaked confessionals. Turns out his vocals work well meshed with Explosions In the Sky-style post-rock.

“I am just flabbergasted by this. I grew up playing in this park,” Rose-García said. “Not music — freeze tag.”

He added that his songs “may seem confessional,” but that really many are fictional accounts of a character the band calls “Garth,” a self-deprecating sad sack who “hates his job.” Garth doesn’t look inward enough and his friends realize his problems begin with a lack of accountability. He mined four onstage songs from this persona.

• MORE SHAKEY: Graves on new album, 'Can't Wake Up,' opening for Paul McCartney at ACL Fest

Simultaneously familiar and arresting, Rose-García capitalized on a pivotal 20-minute window where he had ACL Fest 2018 to himself — folks began to migrate and jostle for positioning at bigger stages after his opening offerings for Arctic Monkeys and Travis Scott.

“You’ve got a lot of choices,” he admitted. “It means a lot to participate with all the insane bands.”

Shakey Graves covered Kurt Cobain’s ”Something In the Way,” too. He shares the Nirvana frontman’s nihilist screeches, only his Americana ballads are detached and breathable.

Beloved duet “Dearly Departed” carried across the park with its sticky “oohs” and ode to a rotten domestic partnership: “You and I both know that the house is haunted.”

“I’ll be your Esme,” a fan sign read, an homage to the duet’s better half, the absent Denver artist Esme Patterson.

Shakey Graves finessed the tricky opportunity, and proved that his elevated set belonged. Three Dualtone Records release in, Rose-García solidified his place as a dude who will be on a mural near a gentrifying neighborhood soon.

• MORE ACL FEST: Catch up with all our coverage