Abigail Washington, Bela Fleck, the Decemberists’ Colin Meloy, Brandi Carlile and Newport Folk producer Jay Sweet watch James Taylor perform from the side of the stage on Saturday.

Just when other New England music fests were starting to grab some limelight, the Newport Folk Festival raised the bar to another level over the weekend, with previously unannounced guests joining in its collaborative spirit.

Even before Sunday’s finale saluted the 50^th anniversary of Bob Dylan going electric at Newport in 1965 with Al Kooper, Dawes, Robyn Hitchcock, Gillian Welch and David Rawlings leading the charge through Dylan covers, Newport delivered a front-loaded bang with surprise sets by My Morning Jacket and James Taylor.

After a rich turn heavy on its prog-ish new album The Waterfall, My Morning Jacket served as Roger Waters’ band on Friday (below), giving textural muscle to Pink Floyd classics “Mother,” “Wish You Were Here” and Dark Side of the Moon climax “Brain Damage/Eclipse,” particularly sublime with Lucius on backing vocals. “And the sun is eclipsed by the moon,” Waters sang to loving lunatics on the grass, and the moon parted rain clouds.

Those who found the Floyd mastermind’s one-off appearance out of place may have been surprised, however, by warm tributes to John Prine, Levon Helm (with daughter Amy Helm also singing on “Wide River to Cross”) and Dylan, whose “Forever Young” found Waters, 71, heartily relishing the chorus. Then, a classy move, Waters introduced each and every member of his ad-hoc band, which also including guitarist G.E. Smith.

That provided the climax for Friday, which also included the Sam Cooke-smooth vocals of Texas upstart Leon Bridges (above), the cathartic indie-folk of the Lone Bellow, the mariachi-tinged desert rock of Calexico, the rousing Strand of Oaks (below, partly evoking early My Morning Jacket), and crisp outfit the Tallest Man on Earth, featuring Dylan-influenced Swedish folk-rocker Kristian Matsson.

Saturday’s buzz was all about James Taylor, who got beyond sound glitches with sweet chestnuts like “Sweet Baby James” and “Carolina on My Mind.” He also introduced Newport founder George Wein as “the man who made this all happen” by inviting the Berkshires resident to the festival. Otherwise, credit for the fest’s recent booking clout goes to producer Jay Sweet, who stood with many of the day’s artists to watch Taylor’s set.

Other Saturday highlights included laidback wordsmith Courtney Barnett (above, who flew in from Australia just for Newport and gained steam with her finger-brushed guitar leads), the likewise raucous Langhorne Slim, sassy songstress Nikki Lane, velvety-voiced country crooner Sturgill Simpson and sensitive indie-pop colorist Sufjan Stevens before the Decemberists wrapped things up with a guest-aided take on Woody Guthrie’s “This Land is Your Land.”

Tommy Stinson (above) arrived late Saturday to storm the stage where North Mississippi Allstars guitarist Luther Dickinson (whose dad Jim produced Stinson’s Replacements) and Puss ‘n’ Boots bassist Catherine Popper had been killing time, dropping dollars out of his pocket as he foraged for a guitar pick before grabbing one off Dickinson’s amp. And Brandi Carlile (below) suggested she may be most potent as an all-acoustic act with flanking twins Tim and Phil Hanseroth, lighting up the stage with her beaming energy and clarion voice.

By the time Sunday rolled around with stars like Hozier, First Aid Kit, Lord Huron and Laura Marling, everything was gravy, with further nods to Newport’s historic track record — and the power of plugging in as a way to diversify the folk tradition. The festival has has reestablished itself as an international draw and near-instant sellout, at least for its long-held Saturday and Sunday lineups. But this year, even without unannounced stars adding to the glimmer, Newport Folk made Friday as essential as any day.

This weekend, the Newport Jazz Festival takes over beautiful Fort Adams State Park for another three days, though Saturday and Sunday still promise the most star power with Cassandra Wilson, Jack DeJohnette, Lisa Fischer, Jamie Cullum, Dr. John, and an encore appearance by Jon Batiste & Stay Human, whose future Stephen Colbert late-night bandleader also played Newport Folk. Still, you never know exactly what will happen, beyond this weekend’s nod to the 60^th anniversary of Miles Davis. Alas, unlike Dylan, who passed on the Newport Folk tribute, there’s no chance of the late trumpeter showing up – again, beyond profound influence.