Boston Calling proves a keeper

photos by matthew j. lee/globe staff/Boston Globe

What began as a potential gamble last year has become a vibrant new tradition for this city’s cultural landscape. Boston Calling launched last May with lofty aspirations to be our first weekend-long rock festival in the heart of downtown. The inaugural edition, with heavy-hitters in indie rock such as the National and Top 40 hitmakers fun., was successful enough to spawn a second one in September.

Now here we are: The sold-out third installment wrapped up Sunday night, capping a weekend that drew more than 60,000 spectators to City Hall Plaza to dance, to pump fists, to drink Sam Adams, to take countless selfies. And then there was Mayor Martin J. Walsh greeting concertgoers on Friday with a big smile and an idle threat: “I was gonna sing a song, but that probably won’t fly tonight.” Good call, Marty.

This past weekend’s Boston Calling was bigger and better, depending on your taste in music. The focus was on tried-and-true indie rock — Death Cab for Cutie, Modest Mouse, the Decemberists, Built to Spill — and with the addition of a kickoff concert on Friday, the lineup swelled to 23 acts playing on two stages over three very long days (so say my worn-out feet from standing on the plaza’s brick for 20-odd hours).

The organizers, including Bowery Presents and the Boston-based Crash Line Productions, loosened the logistical reins a little this year, which brought its own perks and quirks. The beer stands were no longer an enclosed area, meaning attendees could roam the grounds with booze in hand. That, of course, also meant the crunch of discarded cups and cans became an unwanted part of the soundtrack by the end of the night.

There were also more people in attendance. Extra tickets were sold, which attracted 22,000 per day, an increase over last May’s daily average of nearly 20,000. At peak hours, Boston Calling indeed felt full and buzzing, a sea of young folks in shorts, tank tops, and flip-flops who either hadn’t checked the forecast or simply didn’t care about the looming chill in the evenings.

Complaints about the lineup’s lack of diversity — particularly artists of color and the scarce number of bands anchored by women — were warranted. When the festival returns in September, the bill is more eclectic: Lorde, the National, Nas with the Roots, the Replacements, Lake Street Dive, and so on. (Word to the wise: Buy tickets now.)

Still, highlights abounded this weekend: Kurt Vile and the Violators’ spectral spin on stoner rock; the surge and sibling revelry of Tegan & Sara’s power pop; the communal joy of Edward Sharpe and the Magnetic Zeros’ tender folk for the masses; Ben Gibbard shifting from side to side as he led Death Cab for Cutie in a melodically relentless closing set on Saturday; hearing Warpaint’s fuzzy guitar lines ricochet, as if part of the plan, off the plaza’s brick and concrete surroundings; and watching Tigerman Woah!, one of two local bands on the lineup (the other being Magic Man), justify all the hype it has amassed in clubs around town for its junkyard-dog take on American roots music.

For other artists, it was a chance to reconnect after being out of the spotlight in recent years. If there was any rust on Jenny Lewis, it was purely in the pigment of her flame-red hair. Giving off Elton John vibes in cat-eye sunglasses, Lewis was resplendent in a set that surveyed the catalog of her former band, Rilo Kiley, some songs from her last solo album, “Acid Tongue,” and a preview of her forthcoming one (“The Voyager,” due in July). And let’s salute that fitted pantsuit she wore: The blazer, a sort of tie-dyed creation with stars on the lapel, was the weekend’s most talked-about outfit.

As with any event loaded with so many acts, there were outliers. Jack Johnson, the soft-rock crooner, worked better than expected as Friday’s headliner, a smooth operator who was also adept at building and sustaining a loose groove. Brand New represented a harder edge for Boston Calling and galvanized the faithful who thrashed in tandem with the band’s pulverizing wall of sound heavy on metal and punk influences.

With the indomitable Isaac Brock front and center, his head tilted back as he spat words like a slam poet, Modest Mouse closed out the festival on Sunday with a set that spiraled through hits that ignited the crowd, from “Float On” to “The World at Large.” The band’s intensity was surprisingly dexterous, at times sounding like a circus carousel short-circuiting on the brink of combustion.

Just before the Decemberists went on Saturday night, the gray skies took their course and a light but steady rain sent throngs of concertgoers searching for dry shelter; alas, there wasn’t much to be found. Frontman Colin Meloy joked that the weather was setting the mood for his band, calling it the “Pacific Northwest portion of the show.” Indeed, the patter added some unexpected ambience to the rainy-day melancholy lurking beneath several of the songs.

Bastille, a rising English rock band with a major hit (“Pompeii”) and worthy comparisons to the Killers, built its set on pomp and bombast. It’s no wonder these guys will be back in the fall, headlining Agganis Arena on Oct. 13; they’re ready for the big leagues.

Also from England and equally amped up to their usual 10, Frank Turner & the Sleeping Souls roared out of the gate as if they were trying to convert every last soul on the plaza. Turner and his raconteurs are especially beloved around here, which makes sense given that Boston is home to the kindred spirits in Dropkick Murphys.

Amid all the guitar histrionics — and ears are likely still ringing from Built to Spill’s blistering set — a group like Phosphorescent really stood out. With Matthew Houck on vocals and guitar, he led his band through a wide-open tour of cosmic country tinged with prog-rock sprawl, like some gonzo mashup of Hank Williams and Pink Floyd. They made a lasting impression at an event that has already accomplished that and put Boston, finally, on the festival map.