Gary Austin, the founder of the influential improvisational theater troupe The Groundlings, died on Saturday at Cedars-Sinai in Los Angeles following a long illness. He was 75.

Austin had been battling cancer for several years, but remained active teaching and performing. His daughter, Audrey Moore, told Variety the Austin was surrounded by family members and friends who were serenading him.

Austin was a widely admired improvisational teacher of thousands of students, along with being a writer, director, and musical performer. His improvisational teaching technique involved creating scenes based on arbitrary suggestions with performers then committing to agreement on the premise of the story — no matter how far-fetched — and then performing to reflect the truth of the scene and characters.

His students included “Saturday Night Live” cast members Laraine Newman, Phil Hartman and Chris Kattan, Mindy Sterling, Helen Hunt, Paul Reubens, Jennifer Gray, Paul Feig and Helen Slater. Hunt acknowledged Austin during her acceptance speech after winning the best actress Academy Award in 1998 for “As Good as It Gets,” saying, “I would like to thank my acting teachers — Lurene Tuttle, Gordon Hunt, Larry Moss, Gary Austin — for giving me a way to learn about myself and the world and a way to express myself.” His other students included Oscar nominees Lindsay Crouse and Pat Morita.

Austin, a native of Oklahoma, earned a degree in theater arts at San Francisco State in 1964 and broke into show business by becoming a stage manager for the improvisational comedy group The Committee. He started working with Second City’s Del Close to develop characters, improvised with the Comedy Store Players, and performed stand-up.

In 1972, he formed the Gary Austin Workshops, which began to perform at various venues in Hollywood. He founded The Groundlings in 1974, which moved into its current Melrose Avenue headquarters in 1975. Austin directed portions of Lily Tomlin’s Emmy-winning comedy special that year for producer Lorne Michaels, who asked him subsequently to come to New York to direct the cast of “Saturday Night Live,” but Austin opted to remain in Los Angeles to work with The Groundlings.

Reubens created his signature Pee-wee Herman character at the Groundlings in 1978, wearing a too-small gray suit that Austin used when he was auditioning for nerdy characters.

Austin left The Groundlings in 1979 due to creative differences, but returned to direct shows in 1990 and on several other occasions. He also wrote and performed two solo shows, “Church” and “Oil,” and had been recording an album of his songs with his wife, Wenndy McKenzie, and Matt Cartsonis.

Aside from McKenzie and Moore, Austin is survived by a sister, two brothers, a grandson, and three great-grandchildren. Funeral arrangements are pending. In lieu of flowers, donations can be made at https://www.youcaring.com/garyaustin-787562

Tributes began to appear on Saturday night. The Groundings Instagram page posted the messages “A vision, an inspiration, a father to us all, thank you. #RIPGaryAustin” and “RIP Mr. Gary Austin, the founder of The Groundlings Theatre. Our deepest condolences to his loved ones. Thank you for giving us a dream, a voice, a legacy and a family. You will be missed.”

Actress Wendi McLendon-Covey wrote, “RIP Gary Austin, founder of the @groundlings ! But kudos on a life well-lived!”

RIP Gary Austin, founder of the @groundlings ! But kudos on a life well-lived! — Wendi McLendon-Covey (@wendimclendonco) April 2, 2017

Newman tweeted, “The first director of The Groundlings, Gary Austin, has passed away. No words.”

The first director of The Groundlings, Gary Austin, has passed away. No words. https://t.co/wJpT1dU3K0 — Laraine Newman (@larainenewman) April 1, 2017

Kattan, whose father Kip King was an original member of The Groundlings, tweeted a tribute: “I don’t know what my dad or I would have ever become without you. So grateful for your teachings. RIP #GaryAustin”