Of Irish/English ancestry, Agnes Moorehead was born in Clinton, Massachusetts (about 50 miles west of Boston), the daughter of a Presbyterian minister (her mother was a mezzo-soprano) who encouraged her to perform in church pageants. At age three she sang "The Lord Is My Shepherd" on a public stage and seven years later joined the St. Louis Municipal Opera as a dancer and singer, staying there for four years. In keeping with her father's dictum of finishing her education first (then doing whatever she wished to do with her career), Agnes attended Muskingum College (Ohio) and, subsequently, the University of Wisconsin, where she graduated with an M.A. in English and public speaking, later adding a doctorate in literature from Bradley University to her resume. When her family moved to Reedsburg, Wisconsin, where her father had a pastorate, Agnes taught public-school English and drama for five years. In between, she went to Paris to study pantomime with Marcel Marceau.
In 1928 she began studies at the American Academy for Dramatic Arts and graduated with honors the following year. In order to supplement her income, Agnes had turned to radio early on. She had her first job in 1923 as a singer for a St. Louis radio station. Her love for that medium remained with her all her life, and, from the 1930s to the 1950s, she appeared on numerous serials, dramas and children's programs. She was Min Gump in "The Gumps" (1934), the Dragon Lady in "Terry and the Pirates" (1937), Margot Lane of classic comic strip fame in "The Shadow", Mrs. Danvers in "Rebecca" and the bedridden woman about to meet her end in "Sorry, Wrong Number" (acting on the airwaves was so important to her that she would insist on its continuation as a precondition of a later contract with MGM). Significantly, through her radio work on "The Shadow" and "March of Time" in 1937, she met and befriended fellow actor Orson Welles. Welles soon invited her to join he and Joseph Cotten as charter members of Welles' Mercury Theatre on the Air. Agnes was involved in the famous "War of the Worlds" broadcast of 1938, which attracted nationwide attention and resulted in a lucrative $100,000-per-picture deal with RKO in Hollywood. The Mercury players (the other principals were Ray Collins, Everett Sloane, Paul Stewart and George Coulouris) packed up and went west.
In 1941 Agnes appeared in her first film, the iconic Citizen Kane (1941) as the titular character's mother. She received the greatest critical acclaim of her career for her emotive second screen performance, as Aunt Fanny Minafer in The Magnificent Ambersons (1942). In addition to being voted the year's best female performer by the New York Film Critics, she was also nominated for an Academy Award. Through the years Agnes would be nominated three more times: for her touching portrayal of the jaded but sympathetic Baroness Conti in Mrs. Parkington (1944); the title character's Aunt Aggie in Johnny Belinda (1948); and Velma, the hard-boiled, suspicious housekeeper of Bette Davis in Hush...Hush, Sweet Charlotte (1964), co-starring her old friend Joseph Cotton. Other notable film appearances included Jane Eyre (1943) with Welles, The Woman in White (1948) as Countess Fusco, The Lost Moment (1947) as a 105-year-old woman) and Dark Passage (1947), a film-noir in which she had third billing behind Humphrey Bogart and Lauren Bacall as the treacherous, malevolent Madge Rapf. She had a rare starring role in the campy horror movie The Bat (1959), giving (according to the New York Times of December 17) "a good, snappy performance".
On Broadway she appeared in several noted plays, such as "All the King's Men" and "Candlelight". She enjoyed success with "Don Juan in Hell", touring nationally, the first time (1951-52) with 'Charles Laughton' and Cedric Hardwicke, the second time (receiving fewer critical plaudits) with Ricardo Montalban and Paul Henreid in 1973. She also starred with Joseph Cotton in "Prescription Murder" (1962), which, while not a great critical success, was much liked by audiences and introduced a famous detective named Lieutenant Columbo. Agnes performed many times on television before landing the role of Endora on the hit series "Bewitched" (1964). One particularly interesting part came her way through director Douglas Heyes, who remembered her from "Sorry, Wrong Number" and cast her in the lead--and only--role in "Twilight Zone: The Invaders (#2.15)" (1961) as a crotchety old woman in an isolated rural home who finds herself battling "invaders" from outer space. She never utters a word throughout the entire episode but in a tour-de-force performance runs the gamut from irritation to terror to determination. It is one of the most popular and fondly remembered episodes of that classic series.
Of course, the genial Agnes Moorehead's most famous role, and the one she has been immortalized for, is as "good witch" Samantha's (Elizabeth Montgomery)'s flamboyant mother, Endora--the bane of Samantha's husband Darrin's existence--though that was not a role the actress wished to be remembered for, in spite of several Emmy Award nominations.