A native New Yorker, Adams served in the US Marines during WWII and decided to pursue a showbiz career after the war. He began making appearances as a standup comic, performing a routine loaded with comic impressions. In 1954, he was a winner on "Arthur Godfrey's Talent Scouts" (CBS) which in turn led to appearances on variety series, like "Saturday Spectacular" (NBC, 1956) and "The Steve Allen Show" (NBC), before he landed a regular berth on "Perry Como's Kraft Music Hall" (NBC, 1961-63). He subsequently joined former writing partner Bill Dana as a clueless house detective at a hotel on "The Bill Dana Show" (NBC, 1963-65). Adams later joined Rupert Crosse in "The Partners" (NBC, 1971-72), as a pair of detectives always getting into crazy situations. He tried his hand hosting the syndicated "Don Adams Talent Search", which offered neophytes the opportunity for a Hollywood contract by recreating classic movie scenes. Between 1985 and 1989, Adams filmed 66 episodes of the low-budget sitcom "Check It Out!", in which he played the manager of a supermarket. The shows were taped in Toronto and played on Canadian TV and in the States in syndication on the USA Network.
In between on-camera assignment has provided character voices for animated series. His "Inspector Gadget" (syndicated, 1983-84) was clearly akin to Maxwell Smart and he played a younger version of the Inspector in "Gadget Boy & Heather" (syndicated, 1995), as well as providing the voice of the Brain in the live-action 1999 version starring Matthew Broderick. Adams had made a handful of sporadic film appearances, including "Jimmy the Kid" (1982) and a cameo in "Back to the Beach" (1987). In 1993, he made his screenwriting and directing debut with the direct-to-video release "Shreck", a thriller about teenagers who resurrect a serial killer. However, audiences could never forget Adams' hilariously clipped, deadpan delivery as Maxwell Smart, and the actor spent much of the latter days of his career fondly recalling the character when being honored at salutes to classic TV by NBC, TV Land, A&E and their brethren before his death in 2005.