Scott was born in Pittsburgh, Pennsylvania. During World War II he served in the U.S. Army's First Motion Picture Unit (reporting to Lt. Ronald Reagan), where he worked with such animators as Frank Thomas. After the war, he became what was then known as a "story man" at Warner Bros., working under director Arthur Davis. He later worked at the cutting-edge studio United Productions of America where he was one of the writers who adapted Dr. Seuss's original story for the 1951 Academy Award-winning short Gerald McBoing-Boing, which later became a television show, as well as adapting the 1953 Academy Award-nominated short film of Edgar Allan Poe's The Tell-Tale Heart. Scott began work as a voice actor as well when he joined Jay Ward as head writer and co-producer, and voice acted in such television series as The Rocky and Bullwinkle Show (most notably as Bullwinkle, as well as Dudley Do-Right). In a 1982 interview, Scott said, "I got a call from Jay Ward asking if I’d be interested in writing another series, an adventure script with a moose and a squirrel. I said, 'Sure.' I didn’t know if I could write an adventure with a moose and a squirrel, but I never turned down a job." " He also wrote many commercials for General Mills because General Mills had bankrolled much of The Rocky and Bullwinkle Show, and the Quaker Oats Company, most notably those for Cap'n Crunch cereal. The voice of Rocky, Nell Fenwick and many of the feminine roles was performed by June Foray, although Scott's wife Dorothy voiced several female parts as well. Scott also starred on George of the Jungle as George, Super Chicken, and Tom Slick, as well as Fractured Flickers and Hoppity Hooper. Scott also had done live-action acting on the television show The Duck Factory which starred Jim Carrey, as well as featuring noted voice actors Don Messick and Frank Welker. In the episode "The Annie Awards", Scott plays the emcee at an award ceremony for cartoonists.
Toward the end of his career, Scott worked for Walt Disney Studios, where he voiced Moosel on The Wuzzles, and was Gruffi Gummi in Disney's Adventures of the Gummi Bears (he was succeeded by Corey Burton after his death). Gummi Bears, his last role, had also reunited him with June Foray, his Rocky and Bullwinkle co-star. Scott was also a fine singer and performer, active with a Little Theatre group in Tujunga called the Foothill Curtain Raisers. He was especially well known for his talents interpreting Gilbert and Sullivan, and did much to encourage aspiring actors and musicians. He donated great amounts of time to tutoring young people in difficulty.
Scott died of a heart attack on November 29, 1985 in Tujunga, Los Angeles, California. He was survived by his wife, Dorothy, and their three children. Because of this, further episodes and seasons of The Wuzzles were canceled, and Scott's roles in Disney's Adventures of the Gummi Bears were all recast with different actors.