WHAT DOES an actor do when his successful television series ends? He goes back to his roots. There is life after television, as comic actor Larry Storch will assure you.

Although the scrappy Storch has appeared in character roles on more than 200 television programs, from "Car 54, Where Are You?" to "Archie Bunker's Place," he is probably best remembered for his role as Cpl. Randolph Agarn, the scheming jerk in the ABC situation comedy "F-Troop," a military farce about a bumbling cavalry outpost after the Civil War, with Forrest Tucker and Ken Berry. The show ran from 1965 to 1967 and is still in reruns. Storch even had his own live television show in 1950, a summer replacement for "The Jackie Gleason Show."

But television fame is fleeting, and an actor has to eat. So Storch has done it all since then, from nightclubs to commercials to "The Love Boat," relying on his early training as a nightclub comic.

Now Storch is appearing in the Houston Grand Opera's touring production of "Porgy and Bess," currently at the Kennedy Center Opera House. His role, the malicious, drawling detective, is "Porgy's" only non-singing role, and Storch milks the part, earning hisses and boos at the curtain call. The only white member of the cast, Storch says he is taking singing classes while on the road with the show.

Storch, 58, spent 16 of his early years as a standup comic and impressionist, beginning in the Catskills resorts. He assembled an arsenal of dialects and accents during those days, and snaps into a perfect Yiddish dialect when recalling his start.

During "Porgy's" stay at the Kennedy Center, Storch and his wife, Norma Booth, an actress and now Storch's publicist, spend a lot of time at Le Jardin, where Storch clowns around and acts like he owns the place. Which he does, in a way: the couple became partners in the Washington restaurant six years ago. The Storches live in Hollywood, but will be spending the next several months on the road with "Porgy." They hope to put together a nightclub comedy act in the Stiller and Meara mold after this tour.

Like many comedians, Storch says his roots in comedy can be traced back to school days, where he was a disruptive influence in the classroom. "In high school I was invited never to come back," he laughs. After he left high school, he made the rounds of "all the lowdown theaters in Harlem. This was during the Depression years, and I'd take home $2 a night. My parents were delighted to see me come home with $2. My father was a cab driver, and with the $3 he brought home, that fed us."

Born in Harlem, Storch originally planned on a career playing baseball. He was a catcher with the Seals, a black semipro league. "And the Giants wanted to send me to a farm team in New Jersey, $75 a month. But then an agent heard me and said I'll give you $10 a night. So he started me out in Boston's Scully Square, which is a pretty tough neighborhood."

Storch battled his way into better houses and met many stars on their way up. He liberally peppers his conversations with famous names, and it can be disconcerting--when Storch drops a name, he becomes the person he's talking about: Gene Kelly, James Cagney, Sammy Davis Jr.

He tells a long tale of advising Sammy Davis Jr. not to include impressions in his fledgling act. "I told him, 'Sammy, those voices will never work coming out of a black face.' This was in the days when blacks weren't allowed in the casinos. They could entertain there, but they couldn't enter them. But he insisted, and I showed him what I knew. And of course he was a tremendous hit.

"And then there was the time I told Tony Curtis, 'Listen, kid, you'll never be an actor, don't even try. You're a good-looking kid--become a model.' Well, of course, I had to eat my words again." Many of Storch's movie roles were in Tony Curtis vehicles: "The Prince Who Was A Thief," "40 Pounds of Trouble," and "Captain Newman, M.D."

Washington was a frequent stop in his standup days. Storch recalls playing the now defunct Cairo Club, under the Cairo apartment building. Now Storch takes his standup act to Las Vegas and New York, where he plays clubs such as Rodney Dangerfield's. He also does commercials (he has been the voice of McDonald's' "Captain Crook" and "Hamburglar" for more than 10 years) and an occasional feature film. His most recent role was the guru in Blake Edwards' "S.O.B."