Morris was born to a Jewish family in The Bronx, New York, the son of Elsie and Hugo Morris, a rubber company executive. During World War II he was assigned to a United States Army Special Services unit where he was the First Sergeant. Maurice Evans was the company commander and Carl Reiner and Werner Klemperer were soldiers in the unit. Based in Honolulu, the unit entertained American troops throughout the Pacific. He came to prominence in appearances on Sid Caesar’s Your Show of Shows (a live sketch comedy television series appearing weekly in the United States, from 1950 to 1954). Morris appeared twice in 1957 in episodes of the short-lived NBC comedy/variety show The Polly Bergen Show. Although Morris was a classically trained Shakespearean actor, he is best remembered for playing the wily and over the top “mountain man” character Ernest T. Bass on The Andy Griffith Show. Also, he played George, the TV mechanic in the episode: “Andy and Helen have their Day” on the Andy Griffith show. He had lampooned southern accents while in the army at Fort Bragg, North Carolina. He starred in one of the more comical early hour-long Twilight Zone episodes, “I Dream of Genie”. Other roles included that of Elmer Kelp in The Nutty Professor, a movie studio clerk in the short film Star Spangled Salesman, and an art appraiser in an episode of The Dick Van Dyke Show. He also had appeared in several Broadway shows including the highly regarded 1960 revival of Finian’s Rainbow as Og the leprechaun opposite Bobby Howes as Finian. He played the role of Schmidlap in Way… Way Out and appeared in the 1962 movie, Boys’ Night Out starring Tony Randall, Kim Novak and James Garner.

Morris was first heard in animated cartoons in the early 1960s. He and Allan Melvin teamed up for a 50-episode King Features Syndicate series, Beetle Bailey, for which he and Melvin also wrote a number of episodes. He also provided the voices for Gene Deitch’s Academy Award-winning Munro, about a four-year-old boy who was drafted into the Army. Beginning in 1962, Morris played a variety of voices in many Hanna-Barbera series including The Jetsons as “Jet Screamer” who sang the “Eep opp ork ah ah!” song, (said to be Morris’ first work for Hanna-Barbera) and The Flintstones. He was the original voice of Atom Ant and provided the voice of Mr. Peebles in the Magilla Gorilla series, teaming up again with Allan Melvin who performed the voice for Magilla. In another series Morris was heard as the voice of Breezly Bruin which was similar in tone with the Bill Scott vocalization of Bullwinkle. Morris had a disagreement with Joseph Barbera prior to production of the 1966-1967 season of Magilla Gorilla and Atom Ant and all of his voices were recast, mostly using Don Messick. Years later the two men reconciled and Morris was back doing those voices and others. Morris also voiced the characters Professor Icenstein and Luigi La Bounci in the animated series Galaxy High. Morris provided the original vocalizations for the Hamburglar (“Robble, robble, robble”) in McDonald’s 1971 ad campaign, which Morris also directed. He is also remembered by Filmation and Archie Show fans as the voice of Jughead Jones throughout the life of the franchise. Morris provided the voice of Wade Duck in the U.S. Acres segments of Garfield and Friends, and voiced Webbly in Bobby’s World and Flem in Cow & Chicken. Morris supplied the voice of the koala in TV commercials for Qantas from 1967 through 1992 (saying the tagline, “I hate Qantas”), and voiced the character of Gopher in the Disney featurettes Winnie the Pooh and the Honey Tree and Winnie the Pooh and the Blustery Day.

While Morris continued to make himself available for voice and sound effect roles, he also began a new career in voice directing. Among the projects he directed are Police Academy, Richie Rich, Bionic Six, Goin’ Coconuts, Pole Position, Galaxy High, The Snorks, The Mighty Orbots, Rose Petal Place, The Dogfather, Dragon’s Lair, Tom and Jerry: The Movie, Turbo Teen, Cabbage Patch Kids: First Christmas, Little Clowns of Happytown, The Little Wizards, Space Stars and Kidd Video. Morris directed Doris Day in her final film With Six You Get Eggroll in 1968. Other films he directed were Don’t Drink the Water and Who’s Minding the Mint? Mel Brooks occasionally cast Morris in his films. For example, he played Brooks’ mentor psychiatrist Dr. Lilloman in the 1977 comedy High Anxiety, the emperor’s court spokesman (“Here, wash this!”) in History of the World, Part I, and played a bum named Sailor living in the streets in 1991’s Life Stinks. In 1984, he played Dr. Zidell in Splash, a film directed by Ron Howard (the two had first worked together on The Andy Griffith Show). He worked with his old friend and trouping partner Sid Caesar as nervous Jewish tailors in the 1998 movie of Ray Bradbury’s The Wonderful Ice Cream Suit. In 1986, he reprised his famous role as Ernest T. Bass in the high-rated TV movie Return to Mayberry. Morris also directed some episodes of Hogan’s Heroes and The Dick Van Dyke Show.In 1994, Morris voiced Zinn-a-Zu the Bird, Garfield the Third Fish, the Sneetches and Mr. Fox in Storybook Weaver, and later in 2004, remade as Storybook Weaver Deluxe. Near his death, he played Flem on Cow and Chicken.

On May 21, 2005, Morris was found unconscious by his two divorced wives, Mary Helen McGowan and Dolores A. Wylie. Morris was rushed in an ambulance to the hospital, but died on the way. After an autopsy was performed, the doctor discovered that the 85-year-old had been suffering from heart disease and pneumonia. He is entombed in Laurel Gardens Wall crypt at Hillside Memorial Park Cemetery in Culver City, California.