She received an Academy Award nomination and a Golden Globe for Best Supporting Actress for her performance as a lovelorn aunt in I Remember Mama (1948). Over the next four decades, she worked in film and television, typically portraying maids, secretaries, waitresses, or gossips, often in Westerns, and had a recurring role as Henrietta Porter, a newspaper publisher, in Trackdown (1957–1959), starring Robert Culp as Texas Ranger Hoby Gilman. In the episode entitled "The Vote", Henrietta Porter advocates for women's suffrage: "Women should have the right to vote. Women should be in politics. They can't do any worse than you men!" For her guest appearances in many Westerns, Corby in 1989 won a Golden Boot award.
Her best-known role came as Grandma Esther Walton on the made-for-TV film The Homecoming: A Christmas Story (1971), which served as the pilot for The Waltons. Her husband, Zebulon Walton, was portrayed by actor Edgar Bergen in the film. Corby went on to resume her role on the weekly television series The Waltons. (She was the only adult actor from the original Homecoming pilot to carry her role over to the series.) Actor Will Geer played her husband in the series from 1972 until his death in 1978, at which time the character of Zebulon Walton was also buried. The series ran from 1972 to 1981, and resulted in six sequel films. For her work in The Waltons, she gained three Emmy Awards and three more nominations as Best Supporting Actress. She also won a Golden Globe award for best supporting actress in a TV series for the show The Waltons, and was nominated another three times. She left the show early in 1977, owing to a massive stroke she had suffered on 10 November 1976, which impaired her speech and severely limited her mobility and function. She returned to the series during the final episode of the 1977–78 season, with her character depicted as also recovering from a stroke.
She remained a regular on The Waltons through the end of the 1978–79 season, with Esther Walton struggling with her stroke deficits as Corby was in real life. Although Corby was able to communicate after her stroke, her character's lines were usually limited to one word or one-phrased dialogue, such as "No" or "Home"; her role dropped to recurring during The Waltons' final two seasons, and she later resumed her role as Grandma Walton in five of the six Waltons reunion movies between 1982 and 1997.
Ellen Hansen married Francis Corby, a film director/cinematographer who was two decades her senior, in 1934; they divorced in 1944. The marriage did not produce children and she never remarried. Francis Corby died in 1956.
She had a stroke in November 1976 from which she recovered and returned to her role on The Waltons in March 1978. According to Michael Learned, who played Olivia Walton, Will Geer may have saved her life. When she failed to show up for work, Geer immediately suspected something was wrong and went with the show's producers to her home, where they found that she had suffered a stroke. Her stroke was written into the show, with Grandma Walton also suffering a stroke and struggling to regain her speech. Following her stroke, she was supported by her friend, carer and travelling companion Stella Luchetta, with whom she'd become friends in the 1950s, and who lived with her until her death.
Her final role was in A Walton Easter (1997). In 1999, following several years of declining health, Corby died at age 87 at the Motion Picture & Television Country House and Hospital in Woodland Hills, Los Angeles. Her memorial site is in Forest Lawn Memorial Park, Glendale, California.
^Billy Hathorn, "Roy Bean, Temple Houston, Bill Longley, Ranald Mackenzie, Buffalo Bill, Jr., and the Texas Rangers: Depictions of West Texans in Series Television, 1955 to 1967", West Texas Historical Review, Vol. 89 (2013), p. 104
^"Ellen Corby". Los Angeles Times. Retrieved 15 September 2014. In late 1969, Ellen Corby and I, along with 120 others, spent some months in the jungles of the Himalayan foothills near Rishikesh, India, becoming teachers of Transcendental Meditation.
^"Grandma Walton in Racine". The Journal-Times. Racine, Wisconsin: Ancestry.com#Newspapers.com. 24 August 1978. p. 42. (Subscription required (help)).
^"Obituaries - Ellen Corby; Actress Played Grandma on "The Waltons"". Los Angeles Times. Los Angeles, California: Ancestry.com#Newspapers.com. 17 April 1999. p. 121. (Subscription required (help)).