When Nick Cave & the Bad Seeds taped an appearance on the music television series Austin City Limits, the program’s longtime producer, Terry Lickona said, “Can you believe, after 40 years for ‘Austin City Limits,’ 30 years for Nick Cave, this is the first time they’ve been on the stage in front of our cameras?”

This was a bit of a stretch. Cave’s often-abrasive sound and R-rated persona would not have been a good fit for the program during the 1980s or the 1990s. But in 2002, ACL, which is produced by Austin’s PBS affiliate, KLRU, teamed with the concert promoters now known as C3 Presents to start a music festival of the same name. That has changed the Austin City Limits audience, aesthetic and approach.

“When the festival started, the show had already kind of hit its stride, but I think we had also reached a plateau,” Lickona, 66, said. C3 “wanted the reputation, the legacy, the credibility that the show brought along with it. In the process, it introduced all of these young people to the brand.”

“I still have a hard time thinking of it that way, but it is” a brand, he added.

The festival has insulated ACL and KLRU when revenue sources for public television have become unstable. “Clearly, ‘ACL’s’ the flagship,” said Bill Stotesbery, the KLRU general manager. “It’s been a critical part of building the station.”

Austin City Limits first aired in 1975, with Willie Nelson featured in the pilot, and Asleep at the Wheel and Bob Wills’ Original Texas Playboys on the first episode. Then, as now, it offered intimate and “live-feeling” music television, shot in front of an enthusiastic audience on a smallish stage with lingering takes and close-ups.

A lot has changed in 40 years. In 2010, the show moved from its longtime home on the University of Texas campus to the slick ACL Live at the Moody Theater concert venue. While a two-hour all-star special (“Austin City Limits Celebrates 40 Years”), which airs Friday, emphasizes legacy musicians like Willie Nelson, Jimmie Vaughan, Joe Ely and Robert Earl Keen, the show’s more recent history includes much younger artists, and music that is far afield from country, blues, folk-rock and Texas: bands like Coldplay, Arcade Fire and Queens of the Stone Age.

On the 40th Anniversary special, the Foo Fighters represent the post-punk generation, covering Roky Erickson’s “Two-Headed Dog,” while this season’s premiere episode, airing Saturday, stars Beck. Beck will also play the music festival on Friday (as well on Oct. 10) while Jenny Lewis, Sam Smith, the Avett Brothers and Spoon will tape episodes around their festival appearances.

Even given the show’s current direction, Nick Cave was an edgy choice. During his performance, which will air Nov. 1, the Australian frontman chided the crowd for staying in their seats, played two songs that are too profane for television (they will end up on ACLTV.com), and seemed bemused when a brief solo by the Bad Seeds’ violinist, Warren Ellis, earned a round of applause, as if he were a fiddler in the Texas Playboys.

“Epic. Epic. Epic,” said Charles Attal, the head booker at C3 Presents, of the Cave taping.

Lickona says that Cave’s performance will be “the Tom Waits show of the 21st century for ‘ACL.’ ” When Waits performed in 1978, Lickona’s first year as producer, “it was sort of a head scratcher for a lot of people. It was a far cry from Willie and the types of acts that we had been booking for those first three years.” But it became one of the series’ most beloved episodes.

If Nelson is the quintessential Austin City Limits artist of the last four decades — he has been on the show 16 times — Spoon might take the 21st-century Austin indie-rocker crown. The Oct. 9 taping will be the Austin band’s fourth in a dozen years.

“When I was growing up, Austin City Limits was a show I associated with musicians like Willie Nelson and B. B. King,” Spoon’s frontman, Britt Daniel, said. When performing on the show was first suggested around the release of the band’s 2002 album “Kill the Moonlight,” “I thought, ‘There’s no way we’re going to get that,’ ” Daniel recalled. “But a month later, we did.”

Another Austin band, White Denim, will make its first ACL TV appearance this year. “Definitely could have never imagined playing this place, it’s a great honor,” the band’s frontman, James Petralli, said during the taping.

The current relationship between the show and festival is a licensing deal, with C3 paying KLRU an annual fee to use the name. That means the show has no role in shaping the direction of the festival, but Attal still treasures Lickona’s input.

“Terry’s the most open music fan in the world,” he said. “We talk about music at all times.”

And for Lickona, the success of the festival, and the evolution of the show, means he will never have to repeat the experience he had at the very first ACL festival in 2002, when a college-age attendee asked him what he did.

“I proudly said, ‘Well I’m the producer of Austin City Limits, the TV show,’ ” Lickona remembered. “And you know, she kind of had a blank stare and went, ‘There’s a TV show?’ ”