The influence of Ms. Moore’s Mary Richards can be seen in the performances of almost all the great female sitcom stars who followed her, from Jennifer Aniston to Debra Messing to Tina Fey, who has said that she developed her acclaimed sitcom “30 Rock” and her character, the harried television writer Liz Lemon, by watching episodes of “The Mary Tyler Moore Show.” Many nonactresses also said that Ms. Moore — by playing a working single woman with such compassion and brio — inspired their performances in real life.

Ms. Moore had earlier, in a decidedly different era, played another beloved television character: Laura Petrie, the stylish wife of the comedy writer played by Dick Van Dyke on “The Dick Van Dyke Show.” Also on CBS, the show ran from 1961 to 1966.

Ms. Moore was the lesser star in those days, but she shared Mr. Van Dyke’s background in song and dance, and as a comedy duo they magnified each other’s charm. Ms. Moore transformed and tamed the vaudeville style that had dominated sitcoms, perfecting a comic housewifely hysteria in Laura, made visible in the way she often appeared to be fighting back tears. Her “Dick Van Dyke Show” performance won her two Emmys.

“I heard something in her voice that got to me,” Carl Reiner, who created and produced the show, once said. “I think the fact that Mary and Dick were dancers gave the whole program a grace that very few programs have.”

Mary Tyler Moore was born on Dec. 29, 1936, in Brooklyn Heights. After living in Queens and Brooklyn, her family moved to California when she was 8. Her father, George Tyler Moore, a clerk, and her mother, the former Margery Hackett, were both alcoholics and, Ms. Moore often said, imperfect parents. The eldest of their three children, Mary would outlive both her sister, Elizabeth Moore, who died of a drug and alcohol overdose in 1978, and her brother, John Hackett Moore, who died of cancer in 1992 after Ms. Moore had assisted him in an unsuccessful suicide attempt.

While she was still a child in Los Angeles, Ms. Moore arranged to live with an aunt, choosing to see her parents only on special occasions.