If there were any question about whether Andy Grammer’s real-life persona matches the one he portrays in his ultra-optimistic pop songs about life and love, it was answered Wednesday night at Jammin’ Java in Vienna. The singer-songwriter, 28, consistently beamed throughout the sold-out concert as he breezily played about a dozen songs with a “just happy to be here” attitude.

“This is my first headlining tour — so basically, that means it’s so scary,” he confessed to the audience early in his hour-long set. But he showed few signs of nerves as he cheerfully switched between keyboard and guitar, playing nearly every tune from his upbeat, self-titled debut album (“Fine By Me,” “Love Love Love (Let You Go),” “Ladies”) to a couple hundred people, mostly adult women and girls closer to tween age than not.

Grammer — whose fast-talking lyrics are reminiscent of a Jason Mraz-esque performer — was discovered after years of busking on the Third Street Promenade in Santa Monica, Calif., and he wears his street-performing roots as a badge of honor. “What a wacky, wacky way to make a living,” he mused, telling anecdotes about beatboxing to compete for attention from a monkey and a father-son gymnastic duo.

Still, he managed to find an upside. “It made me who I am,” he declared, proving it with “Biggest Man in Los Angeles,” dedicated to his street-performing buddies: “Those moments on the street, when the crowd would rock with me / I felt like the biggest man, the biggest man in Los Angeles.”

His other tunes took a similar outlook of finding the best in a bad situation — most notably in his catchy breakout single, “Keep Your Head Up” — although he did take time to play one heavy song about the most difficult year of his life.

Pop singer Andy Grammer didn’t depart from his sunny persona at his sold-out show at Jammin’ Java in Vienna, Va. (Kyle Gustafson/FTWP)

For the majority of the time, Grammer’s relentless enthusiasm was infectious, particularly while he was grooving to the love song “Slow.” He took the occasion to leap into the crowd and dance (to the delight of the people gathered around the stage), give his bass player’s mom a hug and then jump back onstage.

Grammer also took a moment to deliver a lecture even he called “cheesy”: “Life is too short to not be doing what you love,” he said emphatically. As he joyfully belted out the lyrics to “Keep Your Head Up” (“This is just a journey / drop your worries / you are gonna turn out fine”), you almost couldn’t help but believe him.