David Ketchum, Who Played the Cooped-Up Agent 13 on ‘Get Smart,’ Dies at 97

David Ketchum, a character actor and prolific television writer known for squeezing himself into vending machines, mailboxes and trash bins as part of his missions as a luckless secret agent on the 1960s sitcom “Get Smart,” died on Aug. 10 at a hospice in Thousand Oaks, Calif. He was 97.

His daughter Nicole Madden, who confirmed his death, said the cause was heart failure.

On “Get Smart,” Mr. Ketchum played Agent 13, who was frequently forced into tight spaces on his assignments for Control, a fictional intelligence agency tasked with foiling the plans of Kaos, an evil cabal bent on world domination.

The show, which ran on NBC from 1965 to 1969 and on CBS from 1969 to 1970, was a playful spoof of the spy thriller genre and an immediate success with viewers.

David Ketchum was born on Feb. 4, 1928, in Quincy, Ill., to Cecil Ketchum, a salesman for the National Cash Register Company, and Flora Ketchum. He was born in an elevator, presaging the perpetually cramped lifestyle of Agent 13.

He majored in physics at the University of California, Los Angeles, with plans to become an engineer, but quickly became interested in acting.

While still in school, he joined the United Service Organizations circuit and traveled the world entertaining soldiers, he told The Times of San Mateo, Calif., in 1965.

“I got interested in what made people laugh,” he told The Times. “I know what makes them laugh in nightclubs, but I wondered just what they laughed at in their homes and under sober circumstances.”

Mr. Ketchum went on to host a radio show in San Diego for seven years in the 1940s, a successful stint spearheaded by Bob Hope and Doris Day, the first two guests he requested.

He joined the sitcom “I’m Dickens, He’s Fenster” as a series regular in 1962, starring as the unskilled carpenter Mel Warshaw. He also played a camp counselor in “Camp Runamuck,” a short-lived comedy about a boys summer camp.

In 1966, he joined “Get Smart” as a replacement for Victor French, whose Agent 44 played a similar role in the show’s first season.

Though he appeared in only 13 episodes, Mr. Ketchum’s character became one of the show’s most enduring jokes.

Agent 13 tended to resent his assignments, and he frequently chimed in with disgruntled quips as he wedged into grandfather clocks, towel dispensers and popcorn machines.

In one episode, Maxwell Smart, the show’s ham-handed protagonist played by Don Adams, threatened Agent 13 with a mission in an incinerator if he refused to help him.

Stuffed in an airport locker, an exasperated Agent 13 replied: “You can’t do anything to frighten me. Last week, I was stationed in a stove. The week before that, in a chimney.”

Mr. Ketchum, who was six feet tall, told The Daily Report of Ontario, Calif., in 1967 that he wasn’t claustrophobic but had “a slight tendency toward motion sickness.” Because of that, his biggest fright on “Get Smart” came when the writers stuffed Agent 13 into a running washing machine.

That report, published near the height of the loopy spy spoof’s popularity, described Mr. Ketchum as “one of the busiest and most versatile talents in show business.”

Mr. Ketchum wrote dozens of episodes of hit sitcoms, including “Happy Days,” “Laverne and Shirley” and “Full House,” as well as for “The Six Million Dollar Man.” In 1974, he was nominated for a Writers Guild of America Award for episodic comedy writing for an episode of “M*A*S*H.”

He also had stints on “The Carol Burnett Show,” “The Andy Griffith Show” and “The Mary Tyler Moore Show.” He reprised his role as Agent 13 in the 1989 television movie “Get Smart, Again!” and a revival of the show in 1995.

He is survived by his wife, Louise Ketchum, a singer whom he married in 1957; two daughters, Nicole Madden and Wendy Ellis; three grandchildren and a great-grandson.

Mr. Ketchum’s connection to confined spaces continued in “The Elevator,” a 1974 television thriller he co-wrote about a group of people stuck in an elevator. His familiarity with the subject matter allowed him to “squeeze the last bit of suspense out of the situation,” The Los Angeles Times wrote in a 1974 review.

More than anything, Mr. Ketchum had a penchant for hiding, The Daily Report said of him in 1967. When he wasn’t disappearing into sofas or plants as Agent 13, The Daily Report said, he hid behind his typewriter, at peace pumping out television scripts.

“I work better in small spaces,” he told The Daily Report.

“My life,” he said, “is a small room.”

Kirsten Noyes contributed research.