Shelton greeted the crowd of beach bums with his token irreverent charm.
"I didn't drag my big ass out here today to play volleyball or go swimming or build sand castles. I came here to drink and play country music. C'mon!" he said to roaring approval.
The tens of thousands of ticket-holders came from 48 states, according to Ticketmaster data. They set up camp as early as 10 a.m., toting umbrellas and food, blankets, and towels for a day on the beach waiting for the concert, which started with Shelton's opener, Nashville newcomers Dan + Shay, at 4 p.m.
"We view this as an opportunity to show what Atlantic City is about," said Liza Cartmell, president of the Atlantic City Alliance, which put on the show with Live Nation.
"People are here to enjoy the beach and the Boardwalk, the shows, the entertainment. Yes, it's tough because three of the properties will have to reinvent themselves," she said of the casinos that may be closing soon. "But there's a lot more to do here than gamble."
Precious Bushatz came up from Okeechobee, Fla. "We love us some country in Florida. My friends are freaking out that I'm here," Bushatz said from beneath her umbrella about 3 p.m., admittedly a few margaritas in, her feet nestled in the sand.
She was attending with her childhood friend Barbara Leuzzi, 53, of Ventnor. Bushatz, 54, came up just for the concert - a belated birthday present to herself.
"I'm a widow looking to marry Blake Shelton," Bushatz said, squinting and smiling in the bright sun. "My husband told me in a dream, 'If it's Blake, it's OK.' "
Staking out a good spot at a free concert typically involves a lot of bored waiting before showtime, but at a free beach concert it amounted to lying around, taking a dip in the ocean, and sipping on $6 and $7 beers. (High prices were spotted around town. Parking was as high as $50 at Caesars.)
"We've got water, sun, seagulls, and country music," said Travis Brady, 23, of Mount Carmel, Pa., sitting about 40 yards from the stage.
Brady attended with four coworkers. The group works in from Pottsville, Pa., at a Wegmans refrigerated warehouse, which is kept at a cool 34 degrees. "The sun's a nice change for us," said Brady, who wore a "Kiss My Country A$" Shelton T-shirt and a cowboy hat.
It took the group four hours to get to Atlantic City from Pottsville - though they took a small detour when their GPS brought them to the wrong Kentucky Avenue.
"It definitely wasn't Atlantic City," said friend Kristen Weinus, 22, of Pine Grove, Pa., throwing a side glance at Brady, the driver, "but we made it."
The viewing area stretched from the north side of the Pier at Caesars (stage end) and Kentucky Avenue (general-admission entrance). At 6:30 p.m., the line to get in was five long blocks. The dunes slowed people's entry to the beach, leaving many to listen from the packed Boardwalk, where the audio was broadcast through speakers.
Concertgoers had to reserve tickets, but for those who funneled in (on time) not knowing they needed a ticket, extras were on hand. Additional lifeguards patrolled to keep tabs on the congested shoreline.
Dan + Shay said in an interview after their performance that the show was the biggest - and had the best view - of anywhere they have performed. Granted, they have been on tour with Shelton only a few months and a year ago, they said, they couldn't have even afforded Blake Shelton concert tickets.
"Now we're on tour with him. It's incredible," Dan Smyers, 26, said backstage. "We're working up the nerves to play basketball with him," Shay Mooney, 22, added, explaining that the big man (Shelton) gets a hoop hooked up backstage to shoot around before performances.
Officials hope the country shows boost spirits in the city where casino closings have cast a shadow over summertime fun.
"People think the decline in gaming means people aren't here - that's a misperception. The people are here," said Jeff Guaracino, chief strategic officer for the Atlantic City Alliance, gesturing to the crowd.
Despite the large crowd, no major incidents were reported as of the close of the show.
"There was one suspicious package - a backpack," Guardian said, "but it turned out it was holding 24 cans of beer. And I'm happy to report the beer didn't explode."
Kelly Shively, 28, of Conshohocken, took the opportunity between bands to cool down in the water. She toted with her a bright yellow sign that read: "Blake, play at my wedding in Nashville!"
The bride-to-be is a huge country-music fan. She and her fiance got engaged in Nashville and will have their wedding in the country-music mecca. Her maid of honor, Audra Miller, 27, of Harrisburg, said her goal was to get Shively close enough to the stage for Shelton to see the sign.
Knowing that would be unlikely, Miller also took the mission to Twitter. "We're just hashtagging away," she said. "If he can't see us on the beach, maybe we'll nab him that way."
Shelton was joined on stage by The Voice Season 4 winner Danielle Bradbery, whom he coached on the show.
The crowd soaked up Shelton's country-boy charm, especially as he appealed to the boozers in the crowd.
Midway through his set, he paused to look out on the sun-kissed masses dancing below and said, "I want to get this concert over with so I can come out there and drink with y'all."