Suzanne Pleshette, 70, a smoky-voiced actress who appeared in hundreds of television programs and was best known as Bob Newhart’s sardonic TV wife in the 1970s, died Saturday night.

She had undergone chemotherapy for lung cancer in 2006, and died of respiratory failure at her home in Los Angeles.

Pleshette was a strikingly beautiful actress and had one of the deepest, most distinctive voices in show business. “Telephone operators have called me ‘sir’ since I was six,” she once said. Yet her dark allure never quite translated into a movie career that was her aim in the late 1950s.

Her talents were easily adaptable across film genres, from westerns to Disney fare. Her most-remembered film role was the schoolteacher killed by crazed gulls in Alfred Hitchcock’s “The Birds” (1963). Yet several of her starring projects were terrible, including the 1965 adaptation of John O’Hara’s book “A Rage to Live,” in which she a was socialite nymphomaniac.

Instead of a career as a front-rank movie actress, Pleshette thrived as a fetching personality on television and in interviews. She proved capable of sassy, well-timed bon mots. To one reporter, she described how she won roles with her best physical asset by saying, “I got every job I ever got walking out of the office.”

Such risqué commentary made her a popular guest on “Hollywood Squares” and Johnny Carson’s “Tonight” show. Her banter with Carson brought her to the attention of Mr. Newhart, and she eagerly agreed to a leading part in his self-titled sitcom.

“When I started in movies they said I’d be this big star, but I was only a moderate one,” she told the Toronto Star in 1989. “Not enough good pictures. It’s important to be in a good piece of work no matter the size of one’s own part.”

She received two Emmy nominations for best actress for her work on “The Bob Newhart Show,” which aired on CBS from 1972 to 1978. She portrayed Emily Hartley, an elementary school teacher married to Mr. Newhart, who played a Chicago psychologist named Bob Hartley.

Pleshette reprised the role of Emily for the ending of CBS’s “Newhart,” Bob Newhart’s successor sitcom of the 1980s in which he was a Vermont innkeeper named Dick Loudon.

In the final episode, Newhart is knocked unconscious by a golf ball. When he wakes, he finds himself in bed with Emily on his old television-show set and tells her about a terrible dream in which he owned a New England hotel.

The episode was regarded as one of the cleverest finishes of a television series, and one of the few times an ending in which “it was all a dream” worked.

In the interim, Pleshette had a long career as a sitcom guest star and in made-for-television movies, the best of which was her Emmy-nominated leading role in CBS’s “Leona Helmsley: The Queen of Mean,” as the social-climbing Manhattan real-estate magnate convicted of federal income tax evasion.

The New York Times television critic, John J. O’Connor, wrote: “Even with prosthetic cosmetics, Ms. Pleshette is considerably more attractive than Mrs. Helmsley, but her performance captures what could very well be the essence of the woman. The portrait is all the more effective for being not entirely critical.”

Suzanne Pleshette was born on January 31, 1937, in New York. Her father, Eugene, became a theater and television executive. Her mother, Geraldine, was a ballerina.

As a child, Pleshette appeared in a revival of Maxwell Anderson’s “Truckline Café” at Sanford Meisner’s Neighborhood Playhouse. She attended a performing arts high school and the now-defunct Finch College, both in Manhattan, and studied social work at Syracuse University before starting her entertainment career in earnest.

In 1958, she won good reviews for supporting roles in Broadway shows such as S.N. Behrman’s drama “The Cold Wind and the Warm” — Meisner, her early mentor, was also in the cast. That same year, she made her film debut in the Jerry Lewis comedy “The Geisha Boy.”

Pleshette also began a prolific television career in such series as “Alfred Hitchcock Presents,” “Ben Casey,” and “The Fugitive.” She received an Emmy nomination for her guest appearance as a happy-go-lucky woman dying of leukemia on a 1961 episode of “Dr. Kildare.” Also that year, she replaced Anne Bancroft as Annie Sullivan in the Broadway play “The Miracle Worker,” and a magazine photo of Pleshette captured the attention of film producer-director Delmer Daves. He cast her in “Rome Adventure” (1962), in the leading role of a teacher who finds love in Italy with an artist played by Troy Donahue.

She married her co-star but the relationship deteriorated quickly. They were divorced after eight months, although she and Donahue put aside differences to act together in Raoul Walsh’s poorly received 1964 western, “A Distant Trumpet.”

Pleshette was married to businessman Tom Gallagher from 1968 until his death in 2000. The next year, she married TV comedian Tom Poston, whom she had known for decades. He died in April 2007.

Survivors include three stepchildren, Francesca Poston of Nashville, Jason Poston of Los Angeles and Hudson Poston of Portland, Ore.

In recent years, Pleshette took guest roles on sitcoms such as “8 Simple Rules” and “Will & Grace,” often as the outspoken mother of a main character.

The parts were not far-fetched. When starring in NBC’s short-lived medical drama “Nightingales” in 1989, she told a reporter: “You call us ‘Charlie’s Angels’ in white uniforms and I’ll sock ya!”