When the Art Ensemble of Chicago plays the Chicago Jazz Festival this month, saxophonist Roscoe Mitchell will be the only original member onstage — the only one of the four founders still alive. But to Mitchell, it’s not about who is performing; it’s about the group’s enduring legacy of pushing boundaries. “The mission hasn’t changed,” says Mitchell, 79. “We always said, ‘Look, if the Art Ensemble gets down to one person, that’s the Art Ensemble.’ We’re doing now what we would have been doing 50 years ago: developing ourselves creatively.”

In 1969, he and three other local jazz musicians — trumpeter Lester Bowie, bassist Malachi Favors, and multi-instrumentalist Joseph Jarman — moved to Paris for a stretch. While there, they performed as the Art Ensemble of Chicago, in a display of hometown pride. The same year, they invited percussionist Don Moye (a native of Rochester, New York) to join them. The group’s shows were spectacles, incorporating Afrocentric costumes and African face paint. Its avant-garde music weaved deep blues, futuristic soundscapes, and funk, embracing unorthodox instruments, such as children’s toys.

Mitchell describes the Art Ensemble in those early years as a collective in the truest sense: The members sold their possessions to get to Europe, practiced eight hours a day, and pooled half their earnings from individual concerts to fund group projects. “We had to become a family in order to survive,” he says.

The group returned to Chicago in 1971 and kept the project going while balancing individual pursuits. Mitchell became an educator, most prominently at Mills College in Oakland, California, and the University of Wisconsin. He has felt an obligation, he says, to inspire new generations of musicians. At a recent one-day class for high schoolers in New York City, Mitchell was having trouble getting the students to focus. “So I held one note for five minutes while keeping eye contact with them the whole time. When I stopped, everyone suddenly exploded with questions.”

For a while, the Art Ensemble would continue to regroup to record and tour, but those efforts tapered off following the deaths of Bowie in 1999, Favors in 2004, and Jarman in January. Moye, who lives in Chicago and continues to play, will perform at the Jazz Festival concert, billed as a 50th anniversary event.

With We Are on the Edge, released in April, the Art Ensemble enters its next phase. The two-disc album, its first since 2006, features an 18-member league of mostly new recruits, including poet Moor Mother, violinist Jean Cook, flutist Nicole Mitchell, and cellist Tomeka Reid. Mitchell describes the newcomers as “the second wave.” He handpicked them for the way they embody the Art Ensemble’s creative ethos.

Some met for the first time only last October, in preparation for a gig at Edgefest, an experimental-jazz event in Ann Arbor, Michigan. That went well enough that Mitchell felt recording and touring was “the next logical step.” Later this year, the group travels to Australia, the Netherlands, Sweden, and Britain.

The rigorous schedule is nothing new for Mitchell, who has been performing since his childhood in Englewood, during a time when jazz clubs filled the South Side. He has memories of seeing the Count Basie Orchestra, Duke Ellington, and Lester Young at the Regal Theater, and of jazz greats like Stan Getz playing clinics for music students at his high school. “I’m from an era of apprenticeship, where all you had to do was to go up to somebody doing something you wanted to do and show them you were interested in learning, and they would take you on,” he says. In a way, he’s doing the same for the Art Ensemble’s new members.

Recently retired from teaching, Mitchell still considers himself a student. He spoke for this story from his home in Madison while watching patiently as laborers finished constructing a sunroom. He plans to sit there every day to work on new commissions and, of course, innovate. “This is what I do. I never have been more excited about learning. I don’t think I’ll ever get bored.”

Details:Art Ensemble of Chicago
Aug. 30. Loop. Jay Pritzker Pavilion.
7:45 p.m. Free. chicagojazzfestival.us