Conway was born in the Cleveland suburb of Willoughby, and grew up in nearby Chagrin Falls. He attended Bowling Green State University in Bowling Green, Ohio, where he majored in speech and radio. After graduating, he joined the Army, following which he took a job answering mail for a Cleveland radio station, where he went on to become a writer for the promotional department. He later did local television work in Cleveland with Ernie Anderson.

He gained a national following from his appearance in the 1960s sitcom McHale's Navy. Afterwards, he starred in a string of doomed series before appearing in several slapstick family films. Of these films for Disney, he was often paired with fellow funnyman, Don Knotts. The most popular of these is probably The Apple Dumpling Gang series of movies.

He is probably best known, however, for his work on The Carol Burnett Show where his unscripted antics often caused his fellow players to fall out of character by bursting out in laughter. Example: Conway and Harvey Korman are having a swordfight duel in medieval garb, and Korman appears to run him through. Conway pulls the thin sword "out", looks at it as if it were a dipstick, and remarks, "Hmm... down a quart!" And Korman convulses.

Conway's work on the show earned him three Emmy Awards. Conway had done an early comedy album with former local TV collaborator - and fellow Clevelander - Ernie Anderson. On several occasions, Anderson would be in the audience and Carol would ask him to stand up and take a bow, without explanation, as if he were a famous celebrity.

Conway's two memorable characters on the Burnett Show were--

"The Old Man," whose shaggy white hair, slow speech, and shuffling gait ran counter to the needed energy levels of the various occupations he was usually found in. His comic inability to get said jobs done--usually with slapstick results to himself, and with many an ad-lib--would both frustrate and 'break up' his fellow sketch performers. "Mr. Tudball," a Swedish-American businessman whose intentions of running a 'ship-shape' office were usually sunk by the bored indifference of his secretary, "Mrs. Whiggins" (Burnett). Conway's stereotypical Swedish accent (especially when frustrated) made any of his lines funny. He would also use this accent for other characters, such as an inept dentist. Conway could also get results with no dialogue, as in a sketch in which he played a tired businessman seeking restful sleep in his hotel--and pestered by a housefly, created only by a sound effect and Conway's gazing after it. After much struggle, he manages to get the fly out of the room through the window; after returning to bed, he hears a persistent knock on his door, gets up to answer it, and opens the door, letting the fly (who was doing the knocking) back in.

Conway's more recent work includes a series of satirical how-to videos in which he plays a diminutive, dark-haired Scandinavian known as Dorf (a variation on "dwarf"), reprising his goofy Mr. Tudball accent.

Conway continues to appear in movies and has cameo appearances in TV series; most of these appearances showcase his comedic talent. Currently, Conway voices the character "Barnacle Boy" in a recurring role on the popular Nickelodeon cartoon series SpongeBob SquarePants. Conway also guest stars occasionally on the CBS sitcom Yes Dear, playing the father of Anthony Clark's stuffy character, Greg, with Conway's old Carol Burnett Show co-star Vicki Lawrence playing his wife, Greg's overbearing mother. Conway gave his voice to one episode of "The New Scooby Doo Movies."

Tim Conway's son, Tim Conway Jr., can be heard hosting the Conway and Whitman radio show on KLSX in Los Angeles, California.

Conway himself, when not working in California, resides in Gallatin, Tennessee.