Bob Gunton is a character actor with 125 credits to his name, including several seasons of "24" and "Desperate Housewives" and a host of movie roles in films such as the Oscar-winning "Argo." Vaguely familiar faces like his are common in the Los Angeles area where he lives, and nobody pays much attention. Many of his roles have been forgotten.

But every day, the 68-year-old actor says, he hears the whispers—from cabdrivers, waiters, the new bag boy at his neighborhood supermarket: "That's the warden in 'Shawshank.' "

He also still gets residual payments—not huge, but steady, close to six figures by the film's 10th anniversary in 2004. Since then, he has continued to get "a very substantial income" long past the age when residuals usually dry up.

"I suspect my daughter, years from now, will still be getting checks," he said.

"Shawshank" was an underwhelming box-office performer when it hit theaters 20 years ago this September, but then it began to redeem itself, finding an audience on home video and later becoming a fixture on cable TV.