2 in 12 Angry Men (1957); the seemingly benign gentleman who tries to prevent the Younger family from moving into a whites-only neighbourhood in A Raisin in the Sun (1961); the voice of Piglet in Disney's Winnie the Pooh productions; Vinnie, one of Oscar's poker cronies, in the film The Odd Couple (1968); and Emil Peterson, the hen-pecked milquetoast husband on The Bob Newhart Show.

[4] After his discharge from the Navy, Fiedler moved to Manhattan and attended the Neighborhood Playhouse, where his classmates included Tony Randall, James Doohan, Leslie Nielsen, Richard Boone and Joanne Woodward.

[8][9] Although best known for his portrayals of meek or high-strung characters, Fiedler occasionally escaped typecasting in roles such as the presidential assassin in an episode of I Spy,[8] a school principal moonlighting as a pimp on Vegas,[10] and Mr. Hengist, a Chief Administrator possessed by the spirit of Jack the Ripper in the Star Trek episode "Wolf in the Fold" (1967).

His many other guest appearances on TV include Columbo, Peter Gunn, Alfred Hitchcock Presents, Perry Mason, Bonanza, Gunsmoke, Cannon, My Favorite Martian, The Munsters, Bewitched, Get Smart, A Touch of Grace, The Rockford Files, Three's Company, Quincy, M.E., The Golden Girls, Banacek and Cheers.

His voice is heard in the Disney features Robin Hood (1973), The Rescuers (1977), The Fox and the Hound (1981) and The Emperor's New Groove (2000), and in Disneyland Records's Winnie the Pooh for President.

[citation needed] Fiedler was also the narrator of several McDonaldland commercials during the 1980s (including when Birdie the Early Bird learns to fly and how the Hamburglar got his stripes).