Far more than just an announcer, he contributed all sorts of outlandish, incongruous comic bits to “Late Show With David Letterman.”Alan Kalter, the announcer for the “Late Show With David Letterman” for some 20 years and a participant in a ridiculous array of comic bits during that run, died on Monday at a hospital in Stamford, Conn., where he lived. He was 78.The death was announced by Rabbi Joshua Hammerman of Temple Beth El in Stamford, the synagogue Mr. Kalter attended. No cause was given.Mr. Kalter would welcome viewers with an opening quip (“From New York, home of mad cab disease … ”) and a recitation of the guest list. He would introduce the nonsensical “secret word” of the day and tell Mr. Letterman what was to be put to the “Will It Float?” test, a recurring comic bit. He would work himself into a lather over this or that and run off down the street shirtless.But, just as incongruously, he once sang a heartfelt version of “Send In the Clowns” for no particular reason, bolting offstage afterward overcome with emotion as the audience stood and applauded. Another time, he turned what at first seemed like some fatherly advice about attending the prom into a painful confessional about going to the prom with his own mother, “her middle-age body squeezed like a sausage into a sequined gown, her makeup and perfume a cruel mockery of the womanhood your hormones crave.”His transformation from announcer to all-purpose comic started early. On his first day, he said, Mr. Letterman, who had an Olympic diver as a guest, had Mr. Kalter jump into a pool while wearing his best suit.“I’m floating on my back, looking up at the cameraman, going, ‘This is what it’s like to announce on Letterman,’” he recalled in an interview on CBS New York in 2015, when Mr. Letterman ended the show.“If you’re going to have a talk show,” Mr. Letterman said on Tuesday in a telephone interview, “you’ve got to have a strong announcer, and he filled that way beyond what is required.”Mr. Kalter replaced Bill Wendell in September 1995, after Mr. Wendell retired. Mr. Letterman said that Mr. Kalter’s audition tape had left no doubt when he and his producer at the time, Robert Morton, heard it.“It was like, ‘Oh, my God, here we go,’” Mr. Letterman said.Mr. Kalter’s voice was already familiar to television viewers by then; he had announced on game shows like “To Tell the Truth” and “The $25,000 Pyramid” and provided voice-overs for numerous commercials. Mr. Letterman’s “Late Show,” though, brought him an entirely different kind of fame. His red hair and rumpled good looks made him instantly recognizable, and Mr. Letterman gave him ample opportunities to display his aptitude for both deadpan and over-the-top comedy.Mr. Kalter in 2015. “I don’t recall the guy ever saying no to anything,” David Letterman said in an interview.John Palmer/MediaPunch /IPX via Associated PressBarbara Gaines, the longtime “Late Show” producer, said Mr. Kalter had fit right into the show’s zaniness.“Alan would good-naturedly do almost anything we asked of him,” she said by email, “which is how we like our people.”Mr. Kalter said that he had always been given the option of declining to do a particularly nutty stunt or asking that it be modified, but Mr. Letterman remembered him as being perpetually game.“I don’t recall the guy ever saying no to anything,” he said, “and I guess that tells us something about his judgment.”And, he added, “it wasn’t begrudgingly — it was, ‘I’m all in.’”But Mr. Letterman also noted that, for him, Mr. Kalter and his music director, Paul Shaffer, were steadying influences.“He and Paul, to me, they were fixtures every night,” he said. “You’d look over and see Alan and see Paul and know that it’s going to be OK just like last night.”Guests, too, found Mr. Kalter to be a calming force.“Appearing with Dave triggered its own unique set of nerves,” Brian Williams, a frequent “Late Show” guest, said on Monday night on his MSNBC news program. “But seeing the smiling face of a nice man like Alan Kalter backstage was always the tonic needed in that moment.”The show may have made Mr. Kalter a celebrity, but he kept a low profile when off the set and at home in Stamford, where he had lived since the 1970s.“I played cards in a poker group for a year and a half,” he told The Stamford Advocate in 2003, “before somebody said, ‘Somebody told me you were in broadcasting.’”As for his “Letterman” job, Mr. Kalter was grateful for the opportunity and the long run.“I loved what they let me be,” he told The Pulteney Street Survey, the magazine of Hobart and William Smith Colleges, where he was once a student, “a 10-year-old, paid for doing stuff my mom would never have let me get away with.”Alan Robert Kalter was born on March 21, 1943, in Brooklyn. He started announcing on WGVA radio in Geneva, N.Y., while at Hobart. The radio job had a fringe benefit.“In my off hours,” he said, “I would create the music tapes for all our fraternity parties from the 45’s that came in to the radio station.”After graduating in 1964 he studied law at New York University, then taught high school English for three years, at the same time recording educational tapes and working weekends in radio in the New York suburbs. The pull of radio eventually proved irresistible.“I left teaching for an afternoon radio show at WTFM,” he told the college magazine, “and was hired to be a newsman at WHN Radio in New York, which quickly became a four-year gig interviewing celebs who came into town for movie and Broadway openings, as well as covering nightclub openings three or four nights a week.”When WHN went to a country format in 1973, he turned to making commercials, and then got into game shows.He is survived by his wife, Peggy; a brother, Gary; two daughters, Lauren Hass and Diana Binger; and five grandchildren.Mr. Kalter’s do-almost-anything commitment to “Late Show,” Mr. Letterman said, was a nice counterpoint to Mr. Letterman’s more laid-back style.“I never liked to put on funny hats,” he said. “Alan would dress like a Martian and make it work.”“He filled in so many blanks on that show,” Mr. Letterman added, joking, “he probably deserved more money.” More