As Hollywood business managers go, Bill Tanner of Tanner, Mainstain, Glynn & Johnson is one the most respected, with an impressive list of loyal big-name clients that includes Michael Keaton (“Birdman”) and Aaron Sorkin (“The West Wing,” Broadway’s “To Kill a Mockingbird”).

Tanner, also known for his real estate and equity investment skills, is Variety’s 2019 recipient of the Business Managers Elite Award, given each year to a business manager for a commitment to philanthropy and to giving back. Tanner will receive the award at a breakfast Nov. 13 at the Montage Beverly Hills.

Tanner is a longtime board member of the UCLA Jonsson Cancer Center Foundation. He started off on its auditing committee, double-checking its financial statements, and in recent years he’s taken an active role on the fundraising committee.

“It’s not easy to ask clients to give to your charity, because they all have their own charities,” says Tanner. “But in the past, my clients have given, and once they start, it’s a recurring contribution. My job is also to talk to clients when they do their estate plans and, if there’s money left over, ask that maybe they put the Jonsson Cancer Foundation in there.”

Tanner and the firm are also active sponsors of the Jewish National Fund and the Alliance for Children’s Rights, and he promotes and supports employee volunteerism and charity initiatives, giving employees time and resources to invest in their chosen charities. He also provides free advice and mentoring to friends and acquaintances on how to properly invest, save and build net worth.

“Obviously, he’s a smart guy,” says his longtime professional partner, Peter Mainstain. “But one of the secrets to his success is his ability to lighten up a room, to make people smile and feel good. He’s got great, long-term friends at different levels — people from school, people from personal relationships — and he’s close with many of his clients. I keep saying, and I mean it, that when I grow up I want to be like Bill.”

A Los Angeles native, Tanner started his career in accounting in 1965 and passed the CPA exam in 1971. In the late ’60s and early ’70s, he worked at an accounting firm that handled Las Vegas hotels, and would spend several weeks out of each month in Sin City auditing the book of the Dunes, the Flamingo and the Horseshoe.

“I was there during ‘the days.’ That’s all I say,” says Tanner, cryptically. “It was before the corporations were involved.”

Mainstain had worked at the same accounting firm and they had played together in three-on-three nighttime pickup basketball games at Hamilton High in West L.A. One fateful day in 1975, they ran into each other on Wilshire Boulevard. By that time, Tanner was on his own, handling tax work fed to him by a UCLA frat brother at the law firm Loeb & Loeb. He thought if he had some help, he might be able to go skiing during tax season, so he invited Mainstain to join him.

“I call that our living together year,” recalls Mainstain. “Bill had an office in one of these executive office suites, and I rented a space there. And the end of that year, we decided, yeah, this is going to work. So in terms of corporate governance records, our firm began officially on June 30, 1976.”

Tanner’s first business management client was writer-producer Tom Patchett (“The Bob Newhart Show,” “Alf”), whose tax returns he did for $75 a year when he had his CPA practice. Years later, Patchett – who remains a client to this day – was writing and producing the Mary Tyler Moore variety show “Mary” (1978) with his then-partner Jay Tarses, and he recommended Tanner’s services to one of its ensemble cast members, Keaton.

Similarly, Tanner has handled Sorkin since the late ’80s, when his play “A Few Good Men” was on Broadway, and “Frasier” creators Peter Casey and David Lee since they were staff writers on “The Golden Girls.”

“One of the reasons our firm has been so successful is the loyalty of the clients,” says Tanner. “In this business, where entertainers switch attorneys, agents and managers so often, they have stayed with us from the beginning.”

Tanner says that, while he doesn’t plan on ever retiring, he may “ease off a little” starting in January. “I plan on letting my partners take over and do a lot of the work I used to do. I will always continue helping them with the real estate, the estate planning and the equities, but in terms of the actual tax work. … I don’t plan on doing another tax return again.”