Marjorie Redmond was born in Cleveland, Ohio in 1924 and was raised in Lakewood by J.V. Redmond, a fire chief, and his wife, Margaret. She first ventured into acting as a member of her high school's drama group, Barnstormers. After graduation, she worked in a bank as a typist and a mail page.

Redmond was the first wife of actor Jack Weston, with whom she developed her acting craft at the Cleveland Play House after they married in 1950. Their Hollywood years began in 1958 when they abruptly quit their parts in the hit Broadway musical, Bells Are Ringing, and left for Los Angeles "in a vintage Volkswagen", fully expecting to have to return to New York. They stayed in Los Angeles together for 18 years as both attained success in television. The couple later divorced. Redmond never remarried.

Beyond that, her theatrical experience ranges from appearing with Nancy Walker in the 1955 revue Phoenix '55 to understudying both Angela Lansbury in the original Broadway production of Stephen Sondheim's Sweeney Todd and Judy Holliday in Bells Are Ringing. Coincidentally, she parodied Lansbury's Jessica Fletcher character on a 1988 episode of Hunter, entitled "Murder, He Wrote".

Films in which Redmond appeared include The Trouble with Angels (1966), Billy Wilder's Fortune Cookie (1966), Alfred Hitchcock's Family Plot (1976) and Woody Allen's Manhattan Murder Mystery (1993).

Redmond may be best known as Sister Jacqueline in The Flying Nun, which aired on ABC from 1967-70. She was nominated for an Emmy for Outstanding Supporting Actress in a Comedy Series for her Sister Jacqueline role during the 1967-68 season but lost to Marion Lorne, who won posthumously for her role as "Aunt Clara" on Bewitched. She made guest appearances on television programs ranging from Ben Casey (1962) through Law & Order (1997). She made a guest appearance on Perry Mason in 1965 as Henrietta Hull in "The Case of the Mischievous Doll". Other credits include a recurring role as Mrs. McCardle in Matlock, two appearances (as different characters) on The Munsters, and one time appearances on Barnaby Jones, Quincy M.E., The Cosby Show, The Sandy Duncan Show, Ryan's Hope, The Donna Reed Show, The Rockford Files, Murphy Brown, and Mama's Family, among others.

Redmond was also well known for her portrayal of sage innkeeper "Sarah Tucker" in a popular series of television commercials for Cool Whip dessert topping during the 1970s.

She played a supporting role in the 1981 Broadway production of Ronald Harwood's The Dresser, which starred Tom Courtenay. In 1999, Redmond appeared Off-Broadway in Playwright Joan Vail Thorne's comedy The Exact Center of the Universe. The Village Voice noted Redmond's presence among the "old pros" in the cast, calling Redmond's performance "solid and funny".