Thompson, a resident of Southbury, Conn., died of lung disease Wednesday at Danbury Hospital, said her son-in-law, Tony Sgueglia.
Once described by New York Times theater critic Walter Kerr as "one of the American theater's finest actresses," Thompson won a Tony for best actress in a play in 1972 for George Furth's comedy "Twigs," in which she played four different roles — a mother and her three daughters — in four linked sketches.
Thompson, Kerr wrote in his review, "does not simply give a stunning performance. She gives four of them."
But it was her role as Kate Lawrence, the staid, upper middle-class Pasadena wife and mother in "Family," that brought Thompson national fame.
The hour-long drama, in which she played opposite James Broderick as her lawyer husband, Doug, ran on ABC from 1976 to 1980 and was praised for truthfully presenting stories that expressed real problems.
Thompson, Los Angeles Times TV critic Cecil Smith wrote in 1976, "is the heart of 'Family,' the fulcrum on which this family turns. She's not Mother Knows Best — God knows! — she's quick-tempered, outspoken and often wrong."
The role earned Thompson four Emmy nominations for outstanding lead actress in a drama series, and she won the award in 1978.
"It saddens me greatly that she's gone," Meredith Baxter, who early on took over the role of older daughter Nancy in the series, said in a statement to The Times on Friday. "She was a formidable teacher and a wonderful woman. I admired her greatly."
Broderick, who died in 1982, once said that "Sada is about as close as we get in this country to British super-actresses like Dame Edith Evans and Dame May Whitty. I'm sure if Sada lived in England, the Queen would have dubbed her Dame Sada a long time ago."
Thompson's various theatrical honors include Obie and Drama Desk awards for her career-changing starring role as the bitter and domineering mother in Paul Zindel's Pulitzer Prize-winning drama "The Effect of Gamma Rays on Man-in-the-Moon Marigolds," which opened off-Broadway in 1970.
Besides her four Emmy nominations for "Family," she received five other Emmy nominations. They include one in 1976 for her supporting role as Mary Todd Lincoln opposite Hal Holbrook's Abe in a segment of the "Sandburg's Lincoln" one-hour drama specials and one in 1991 for a guest appearance on "Cheers."
Born Sada Carolyn Thompson in Des Moines, Iowa, on Sept. 27, 1927, she moved with her family to Fanwood, N.J., several years later.
While she was growing up, her parents often took her to a local theater, where plays stopped on their way to Broadway or before they began national tours.
"I saw stars like Helen Hayes, Maurice Evans, Tallulah Bankhead and Cornelia Otis Skinner," she recalled in a 1987 Associated Press interview. "It was enchanting. I knew that was the world I wanted to be in."
Thompson studied drama at Carnegie Institute of Technology in Pittsburgh (now Carnegie Mellon University), where she met another drama student, Donald Stewart. They were married shortly after her graduation in 1949.
As Thompson began carving out her acting career in the early '50s — she played multiple roles in the first stage reading of Dylan Thomas' drama "Under Milk Wood" in New York in 1953 — Stewart went to work for Pan American World Airways.
He survives her, as does her daughter, Liza Sgueglia; and her brother, David Thompson.