Although still a little young to be as intrinsic to Boston’s musical history as chanting “Dirty Water” at Fenway or driving down Route 128 to “Roadrunner,” Boston Calling has cultivated the kind of big presence in the city that betrays its three years of existence.

Looking past the purely Bostonian touches of Samuel Adams merchandising and sunbathers on City Hall Plaza’s cobblestones regardless of weather, Boston Calling convenes biannually with the intent of showcasing acts that often evade other major festival lineups. Acting in years’ past as early champions of acts like UK synth pop group the 1975 and Australian electronic artist Flume, Boston Calling also couples rising artists with scene veterans like the Pixies, Built to Spill, and the Replacements to the approval of 40,000 attendees each year.

Trevor Solomon, who relocated to Boston in May 2015 to become the talent buyer for festival coordinators Crashline Productions, acknowledges his role in the city’s biggest festival with a bit of self-critique.

“To be completely honest with you, there were younger audiences [this past September], but we could’ve appealed a little more to them,” Solomon said. “At the same time, we have that older audience who have been liking the stuff we’ve been booking, so we just try to find that balance every festival.”

Although September’s festival featured folk heavyweights the Avett Brothers and Grammy award-winning Alabama Shakes, the upcoming May edition boasts the festival’s most mainstream-friendly lineup yet. Headliners include Swedish pop star Robyn, UK house duo Disclosure, and a special performance from pop singer/songwriter Sia, which will be her first East Coast performance in over five years.

“When the offer for Sia came to us, we thought the story behind it was really unique and interesting,” Solomon said. “That’s the kind of stuff we gravitate to.”

Although Boston Calling’s main attractions continue to deviate from the festival’s early days of saluting indie rock royalty like two-time headliners the National, Solomon repeatedly emphasizes his team’s ethos of focusing on the artist’s “story” and not necessarily their status on the Billboard charts.

“I feel we really try to curate our lineup,” says Solomon. “I’m not saying other festivals are doing a bad job nor am I in the business of critiquing them, but I feel like we’ve created something unique in the space we’re living in.”

Part of that uniqueness comes in the form of the festival’s opening slots, which serve as a showcase for Bostonian artists. Although not an original concept in the festival world, the local spot at Boston Calling often heralds an artist’s ascension to national consciousness. Alumni of the opening slot include funk rockers Bad Rabbits, who secured the #1 spot on the iTunes R&B charts in 2014 for their American Love LP, and the electro-pop duo Magic Man, who released an LP on Columbia Records two months after their Boston Calling appearance.

This year’s openers are the festival’s most promising upstarts; rapper Michael Christmas just completed a U.S. tour with Mac Miller, while rock act Palehound netted critical acclaim nationwide in 2015 for their debut LP, Dry Food.

Although Solomon and the festival’s press team declined to comment on recent rumors of nixing their September edition of the festival, cosmetic changes to the festival’s setup additionally promise big changes to come for May.

According to Solomon, his team is currently working on a third stage that will incorporate "comedy elements,” although its placement has yet to be decided within City Hall Plaza. The continued growth of a festival already on City Hall’s front steps might seem worrisome to the city itself, but city officials have nothing but support.

“Boston Calling has shown us the tremendous potential for the future of the plaza,” Laura Oggeri, chief communications officer for the City of Boston, said. “We look forward to continuing our efforts to create an engaging and activated space that Boston's residents and visitors can enjoy year-round.”

Right now, Solomon and his team simply focus on their present task at hand: building on past successes as a roadmap for their future plans.

Singling out the Grammy Award-nominated singer Hozier’s appearance in September, Solomon acknowledges it might be an “obvious choice” to mention him. “When I started working on booking him eight months before the festival though, he was still unknown,” Solomon said. “When he played “Take Me To Church” during the last Boston Calling and I heard the reaction from the crowd, I felt that big sense of accomplishment you don’t get too much at this job.”

However, Solomon doesn’t allow himself or the Crashline team to rest on their laurels. “I felt [proud] for about two minutes though. That’s the amount of time I allow myself to have with that feeling.”

If the promises of May’s festival are any indication, Solomon’s about to have plenty of opportunities for two minutes of pride.

Boston Calling's upcoming lineup: