Koch was also one of the primary writers for radio performers Bob and Ray. It was this association that brought him to the attention of Mad when some of the show's scripts were reproduced in the magazine with caricatures of the star duo drawn by Mort Drucker. Mad eventually published ten Bob & Ray articles in the space of a year and a half, but Koch went on to write more than 300 other pieces for the magazine between 1958 and 1995 on a variety of subjects.
Koch's most enduring contribution to Mad is almost certainly 43-Man Squamish, a fictitious field sport with dadaist rules which became unexpectedly popular in real life, due not only to Koch's ideas and scripting but also to the illustrations provided by George Woodbridge.
Koch was a staff writer for Dave Garroway's Monitor program, turning out 100 pages of material per week, when he was asked by NBC in 1955 to write spot scripts for Bob and Ray's guest appearances. Recalled Koch, "The network preferred to have something written down so they knew what was going out on the air. So I wrote ten spots and they used eight of them. So I sent them ten more and they never did reject another one... I just kind of fell into it." He ended up writing nearly 3,000 comedy pieces for the duo. Among Koch's sketches were the Slow Talkers of America, the Parsley Society of America, Mr. Science, and episodes of "The Gathering Dusk," a soap opera parody starring Edna Bessinger, "a girl who's found unhappiness by hunting for it where others have failed to look." "Tom's stuff couldn't have been more on the button," said Bob Elliott. "Everything he did was funny. he was a gold mine of funny thoughts and exactly what we needed to punctuate what we had already been doing."
"It always started out fairly straight," said Koch. "You didn't know it was humor and it would just slowly veer off into something that was hilariously funny. Some people didn't think it was funny at all." Through all of it, he never had a contract with Bob and Ray; "Sometimes they would give me money and sometimes they wouldn't," said Koch. Like many radio performers, Bob and Ray did not credit their writers; Elliott later wrote, “I feel we didn’t give him a real shake that he should have had."
Koch's professional association with the duo lasted 33 years, though contact was infrequent. Bob Elliott recalled that he and Ray Goulding would only learn where their ongoing storyline segments were headed next by ripping open the envelopes mailed in by Koch: "It was great when the Tom Koch package arrived." Following Koch's death, Elliott told the New York Times that he had only met Koch three times, and that Goulding had met him just once.
He wrote his spots from his home in Indiana, and later, California, where he also wrote for television shows starring George Gobel, Tennessee Ernie Ford, Dinah Shore, Pat Paulsen, Dick van Dyke, and Jonathan Winters. Koch also wrote for The Lucy Show, Petticoat Junction, My World and Welcome to It, My Mother the Car, and All in the Family. Koch's script for the Bob and Ray special "A Cure for California" won an Emmy Award. Koch played a bit part as a janitor on Mary Hartman, Mary Hartman; Koch said, "I didn't like it at all... It scared the wits out of me."
Longtime Mad editor Nick Meglin called Koch a "natural fit" for the magazine. "He was such a polished writer, a very literate craftsman with a far-ranging wit that ran the gamut from hilarious absurdity to wry, brilliant commentary... He had stuff no one else was doing." As with Bob and Ray, Koch wrote from home and only rarely visited the Mad offices. When he did, "he wore a shirt and a tie and a business suit," recalled Meglin. "He was conservative; very smart mustache and trimmed hair, and we're walking around with jeans and sneakers and sweatshirts and stuff."
Koch was born in Charleston, Illinois, and spent his youth in Indianapolis before attending Northwestern University. He published a book of poetry, I'll Remember Indiana, in 1948, and a book about Indiana basketball, Tournament Trail, in 1950. Later with Mad, he published four books under the magazine's imprint. Koch moved to California in 1957, and was married three times.
Discussing his career, Koch said, “People would say I must have had such a great life doing this, people who were engineers, doctors, insurance salesmen or whatever. But it was the kind of work where every morning I would wake up and think, ‘My God, I wonder if I can do it again today.’ There is no way you prepare to do it, or even know how you do it.”
- Pollock, David (2013). Bob and Ray: Keener Than Most Persons. Applause Theatre & Cinema Books\. p. 145. ISBN 9781557838308.