San Francisco’s Golden Gate Park, and the adjoining Haight-Ashbury neighborhood, are hallowed ground in the Grateful Dead’s history — and for Deadheads. The area was the epicenter of the 1960s counterculture movement, and along with a cadre of other bands including Big Brother and the Holding Company, Jefferson Airplane and Quicksilver Messenger Service, the Dead provided the house music. In its early years, the band often played shows throughout the park and the city blocks surrounding it; in 1991, the Dead staged a massive concert at the park’s Polo Field to honor the passing of its longtime promoter and Bay Area concert royalty, Bill Graham.

Decades later, the Haight’s streets were alive on Friday with vendors, buskers and Deadheads, who trickled down Golden Gate Park’s JFK Promenade — where Shakedown Street, the tailgate-meets-street-fair that pops up at every Dead show, lined the road — to the Polo Field, where the show took place. Under an appropriately gray and cool San Francisco summer sky, Dead & Company would take the stage with more than a half-century of history hanging in the air.

Over the last several years, 32-year-old Billy Strings has emerged as one of — if not the most — lauded musicians in the broader jam band ecosystem, playing with revered artists, including Willie Nelson, Phish and Grateful Dead founding members Bobby Weir and Bill Kreutzmann. Strings plays jamgrass, a heavily psychedelic and improvised iteration of bluegrass, and was a fitting opener for the first of these three Dead shows.

Early in his career, Garcia taught banjo and played in folk groups and jug bands; even as the Dead’s popularity swelled int he early ’70s, he formed the short-lived bluegrass band Old and In The Way. Of course, concurrently, Garcia was shredding psychedelic blues-rock with the Dead at acid tests — and Strings embodied this duality in his set, deftly integrating deep jams (a 10-minute jam on his own “Away From the Mire”) with shorter numbers like his breakout single “Dust in a Baggie,” his Grammy-nominated Willie Nelson collaboration “California Sober,” and the traditional “Shady Grove,” a late-career favorite of Garcia’s. And in a special turn, Strings closed his set with “Thunder,” a song he wrote to accompany unused lyrics by the late Dead lyricist Robert Hunter.

In October, Grateful Dead founding member Phil Lesh died at age 84. Lesh’s son, Grahame, frequently performed with his father, and has continued to play Dead music since the elder Lesh’s passing; this weekend, he’s led the “Heart of Town” after shows at San Francisco’s Pier 48 featuring a who’s who of players from the jam world. On Friday, Dead & Company kicked off its second set with “Box of Rain” — a rare Phil-written and Phil-sung Dead tune — and invited Grahame to the stage to sing it. The younger Lesh’s impassioned vocals were outstanding, but so was the bass slung over his shoulder: Mission Control, the instantly recognizable instrument that Phil played as the Dead performed some of its most exploratory music in the early ’70s.

Lesh stayed in the fold for “Playing in the Band,” which on Friday channeled its history as one of the Dead’s most reliable improvisational vehicles. For this “Playing,” Dead & Company stretched out in a way it hadn’t in the show’s first set, venturing to the cosmos with a dense, propulsive jam that landed in a primordial jazz fusion swirl as the band segued into the Weir-written stalwart “Estimated Prophet.” It was the evening’s headiest moment, and a sign of promising things to come musically later in the weekend.

Among Dead & Company’s four players who weren’t in the Grateful Dead, the platinum-selling, Grammy-winning, arena-headlining Mayer naturally gets the most attention. But Chimenti, a longtime creative partner of Weir’s and Burbridge, who before Dead & Company played in the Allman Brothers Band, provided essential rhythmic and melodic underpinning. Dead & Company segued from “Estimated” to fan favorite “Eyes of the World” — a classic pairing dating to the Dead’s beloved late ’70s era — and Chimenti and Burbridge both delivered intricate, extended solos that reaffirmed their critical roles in the band.

The Garcia-Hunter composition about a drunken sailor reckoning with the choices he’s made is among the most profound in the Dead’s extensive songbook. Throughout his career, Strings has covered many Dead songs — but perhaps none as movingly as “Wharf Rat.” Deep in Friday’s second set, he joined Dead & Company for a mammoth version of the song, delivering astounding vocals and trading in his customary acoustic guitar for an electric one. As the jam peaked, Strings and Mayer’s guitars locked into Allman Brothers-styles harmonies — a moment that demonstrated that, as far as the jam world’s next generation is concerned, the kids are alright.

Like every show of Grateful Dead music since Jerry Garcia’s 1995 death, the late Dead bandleader’s spirit hung over the Golden Gate Park audience on Friday night — but doubly so given the auspicious date: what would have been his 83rd birthday. To mark the occasion, Dead & Company encored with one of the Dead’s perennial Bob Dylan covers, “Knockin’ On Heaven’s Door,” as screens on either side of the stage displayed photos of Garcia to roaring audience applause. Mayer and Weir traded heartfelt verses as band concluded Friday’s show on a poignant note.