Adams was born in Manhattan, son of William Yarmy and his wife Consuelo (Deiter). Adams and his brother Richard (who later became an actor, known as Dick Yarmy) were each raised in the religion of one parent: Don in the Catholic faith of their mother, and Dick in the Jewish faith of their father. Dropping out of New York City's DeWitt Clinton High School (comedian Larry Storch was a classmate), Adams worked as a theater usher.

Creators Mel Brooks and Buck Henry, prompted by producers Dan Melnick and David Susskind, wrote Get Smart as the comedic answer to the successful 1960s spy television dramas such as The Man from U.N.C.L.E., The Avengers, I Spy and others. They were asked to write a spoof that combined elements from two of the most popular film series at the time: the James Bond and Pink Panther (Inspector Clouseau) movies.  Get Smart was written as a vehicle for Tom Poston, to be piloted on ABC; when ABC turned it down, NBC picked up the show, which cast Adams in the role because he was already under contract. When Get Smart debuted in 1965, it was an immediate hit. Barbara Feldon co-starred as Max's young and attractive partner (later wife) Agent 99, where she had a great chemistry with Adams throughout the show's run, despite a 10-year age difference, and they became best friends during and after.  Adams gave the character a clipped speaking style borrowed from actor William Powell. Feldon said, "Part of the pop fervor for Agent 86 was because Don did such an extreme portrayal of the character that it made it easy to imitate." Adams created many popular catch-phrases (some of which were in his act before the show), including "Sorry about that, Chief", "Would you believe ...?", "Ahh ... the old [noun] in the [noun] trick. That's the [number]th time this [month/week]." (sometimes the description of the trick was simply, "Ahh... the old [noun] trick."), and "Missed it by 'that much'". Adams also produced and directed 13 episodes of the show. He was nominated for Emmys four seasons in a row, from 1966 to 1969, for Outstanding Continued Performance by an Actor in a Leading Role in a Comedy Series. He won the award three times. The show moved to CBS for its final season, with ratings declining, as spy series went out of fashion. Get Smart was canceled in 1970 after 138 episodes. Answer this question using a quote from the following article:

What was Get Smart?
a spoof that combined elements from two of the most popular film series at the time: the James Bond and Pink Panther (Inspector Clouseau) movies.