NEW ORLEANS — The sound of the New Orleans Jazz and Heritage Festival is a syncopated beat: rooted in Africa, mingled with elements from Europe and the Americas, transmitted through generations, played by hand and determined to get people dancing. The beat doesn’t have to sell a song; it’s a joy in itself. It’s proudly old-fashioned, celebrating its own history. Yet it lives in the immediate present, the moment when music generates motion.

Jazz Fest, as everyone calls it, is as stubbornly exceptional and as proudly nostalgic as the city it reflects. First presented in 1970, the New Orleans Jazz and Heritage Festival became one template for the modern pop festival, like Coachella or Bonnaroo, with music on multiple stages, assorted nonmusic exhibitions, and food and crafts vendors geared to the crowd.

But where other major festivals tend to be brief invasions of their locales, Jazz Fest is an institution, inseparable from the city where it also sponsors free events through the year and supports the only-in-New-Orleans public radio station WWOZ. And where other major festivals have current pop hitmakers as their big draws, along with an undercard of new acts striving to reach the main stage in a year or two, Jazz Fest prizes the regional over the national, putting just a few big names in headlining spots.

Its first weekend this year, which started last Friday, included Lorde, Usher with the Roots, Tom Petty and the Heartbreakers, Elle King, the Trey Anastasio Band, Alabama Shakes and Maroon 5. Its second half, starting on Thursday, has scheduled Stevie Wonder, Dave Matthews, Snoop Dogg and Wilco. Nearly everything else — except, this year, for a contingent of superb bands from Cuba — stays local and familiar, as untrendy as a festival can be. (The festival ends of Sunday.) Onstage during the festival, I saw more sousaphones than laptops.

The visiting pop headliners attract hometown residents and a youth contingent. Out-of-towners — many grizzled and wearing Hawaiian-style souvenir shirts from previous Jazz Fests — return for an annual immersion in Louisiana lore. That means brass bands and Mardi Gras Indians, who perform on stages and — simulating the city’s continuing street traditions — in miniparades through the fairgrounds where the festival is held. It also means blues, zydeco from bayou country and a Jazz Fest touchstone, the gospel tent, where singers, preachers and choirs of everyday worshipers belt out praises and gratitude.

Jazz Fest’s New Orleans aesthetic is defined not by the big pop chorus but by live, danceable grooves. New Orleans audiences appreciate instrumental music; Jazz Fest has long been hospitable to jam bands and, this year, to bands like Tom Petty and the Heartbreakers, whose live sets move toward improvisation. The “heritage” in the festival’s name also looms large. Jazz Fest glorifies genre as much as individual musicianship; New Orleans is full of performers who proudly steep themselves in vintage styles and a shared repertoire, handed down from parent to child and embraced by musicians who move into the city.

New Orleans honors its ancestors, keeping old songs current and paying tribute in ways that go deeper than borrowing surefire hits, although this year’s Jazz Fest had its share of crowd-pleasing Prince covers. Inevitably, over 48 years Jazz Fest has faced generational change and loss; this year’s lineup included sets devoted to definitive New Orleans figures like the traditional jazz clarinetist Pete Fountain and the songwriter Allen Toussaint.

Visiting musicians often adapt to Jazz Fest, not the other way around. Nas, the New York rapper, played with the Soul Rebels, a New Orleans brass band, reminding listeners that “these are my roots, too.”

More subtly, the festival leads listeners to hear musical kinships — particularly, this year, from a Cuban contingent that included Gente de Zona, a reggaetón group that has won a Latin Grammy, and the Septeto Nacional de Ignacio Piñeiro, founded in 1927, playing vintage-style Cuban son. There are longstanding ties between the music of New Orleans and of the Caribbean, particularly Cuba; what Jelly Roll Morton called the “Spanish tinge” was actually the Afro-Cuban rhythms that made their way into New Orleans Mardi Gras music, jazz and R&B.

Bouncing across the fairgrounds field, mingling with second-line brass-band drums, Mardi Gras Indian chants and the hooting, ratcheting two-steps of zydeco bands (like Dwayne Dopsie and the Zydeco Hellraisers), their syncopations joined the New Orleans mix, sounding right at home.

Notable acts from the 2017 New Orleans Jazz and Heritage Festival included:

LORDE Like an emissary from a separate pop planet, Lorde played a headlining set that defied Jazz Fest customs. She had party songs, but they were about feeling isolated; she had beats that she danced to — striding and punching the air — but they were stark and somber. Part of her music, notably backup vocals, was canned. And she brought the same songs from her coming album, “Melodrama,” that she had performed a week earlier at Coachella. But her own singing was impassioned and drew ardent, verse-and-chorus singalongs on songs from her debut album; and she charmed the crowd by singing a snippet from Tom Petty, who was playing on the other main stage, and noting her dangerous attraction to beignets. Three songs into her set, she had noticed the New Orleans difference: “You guys have danced more than the entirety of Coachella,” she said.

USHER AND THE ROOTS Usher didn’t bring his elaborate arena-concert setup or his electronics-loving band to Jazz Fest. Instead, he collaborated with the Roots, reworking his music with live muscle rather than programming, meshing his own songs with soul oldies and testing himself as an old-school soul man. He easily seduced the densely packed crowd, promising “so many ways to love you” and carrying the crest of his set toward a galloping gospel climax. He also shared time with the Roots, ceding the stage to their rapper, Black Thought, for dense, breakneck rhymes of his own.

STANTON MOORE The drummer Stanton Moore, who plays constantly around New Orleans, previewed his next album, due in July: a tribute to Allen Toussaint featuring Cyrille Neville on vocals. Mr. Moore is used to stirring up a dance floor; his drumming was steady and unstoppable, pushing toward peaks. With a drummer’s wit, he switched Toussaint’s “Everything I Do Gonna Be Funky” into a 5/4 meter that might trip up dancers, and kept it funky anyway.

TELMARY Y HABANA SANA The Cuban poet, rapper and songwriter Telmary Diaz didn’t rely on her words alone to get across her socially conscious messages. She had a full Latin band, playing the sinuous rhythms of son and speedy, percussive rumba, surrounding her with melodic refrains.

TRUMPET MAFIA Ashlin Parker’s Trumpet Mafia already lived up to its name with just three trumpeters onstage, sharing arrangements like a big-band trumpet section and then going round-robin on quicksilver, articulate solos. Then came the big reveal: more trumpeters, at least a dozen, swarmed onstage at the Jazz Tent, from 8 years old on up, and they weren’t just there for backup. Many of them stepped forward for impressive solos.

MIDNITE DISTURBERS Bruising but precise, Midnite Disturbers is an alliance of musicians from many brass bands, doubling up to play songs they all know — and where a typical brass band has one sousaphone huffing the bass line, the Midnite Disturbers had a pair, huffing in harmony. The group’s uniform was black T-shirts with individual names on the front — not their own names, but, true to New Orleans musical continuity, the names of musicians they respect.

THE PEDRITO MARTINEZ GROUP Latin pop, propulsive dance vamps and adventurous jazz were all part of the spectrum for the Pedrito Martinez Group, a Cuban band led by Mr. Martinez, a kinetic conga player and a pealing singer, often both at the same time.

MOKOOMBA This band from Zimbabwe sings in the language its members grew up with, Tonga. But its guitar grooves are a Pan-African blend, drawing on the thumb-pianolike guitar picking of older Zimbabwean pop, on the lilting rumba of Congolese soukous and on hints of rock. It was topped with the chameleonic vocals of Mathias Muzaza, who moved from a smooth croon to rasping, riveting incantations.

DWAYNE DOPSIE AND THE ZYDECO HELLRAISERS The button accordionist Dwayne Dopsie is the youngest son of Alton Jay Rubin, better known as Rockin’ Dopsie, who died in 1993. (Dwayne’s brother Anthony, who bills himself as Rockin’ Dopsie Jr., performs at Jazz Fest on Saturday.) Dwayne Dopsie carries on the rowdy, muscular family zydeco tradition: singing in English, pumping out thick chords and suddenly breaking into whirlwind solos.

E’DANA & DIVINELY DESTIN For much of Jazz Fest, New Orleans talent fills the gospel tent (although the Clark Sisters, national gospel hitmakers, had a prime slot on Sunday night). I happened in as E’Dana Richardson was testifying and belting, call-and-responding with rising fervor, over a guitar-scrubbing funk groove delivered by her band and singers. Then she introduced them: her children, nephews and big brother. “This is all family up here!” she exulted.