Early career Dennis made her television debut in 1956 in the soap opera
Guiding Light. She had an early break when cast as an understudy in the Broadway production of
William Inge's
The Dark at the Top of the Stairs (1957) directed by
Elia Kazan. Kazan cast Dennis in her first feature film, a small part in
Splendor in the Grass (1961), which starred
Natalie Wood and
Warren Beatty. Dennis was cast in
Face of a Hero (1960) on Broadway alongside
Jack Lemmon. The play had only a short run, but Dennis received good notices.
The Complaisant Lover (1961–62) by
Graham Greene was more successful, running for 101 performances;
Michael Redgrave and
Googie Withers were also in the cast.
Broadway stardom Dennis achieved Broadway fame with her leading role in
Herb Gardner's
A Thousand Clowns (1962–63), for which she won a Tony award for her performance. She was replaced in the 1965 film version by
Barbara Harris. The show ran for 428 performances. Around this time, Dennis guest-starred on episodes of the TV series
Naked City ("Idylls of a Running Back", 1962, "Carrier", 1963),
The Fugitive ("The Other Side of the Mountain", 1963),
Arrest and Trial ("Somewhat Lower Than the Angels" 1964), and
Mr. Broadway ("Don't Mention My Name in Sheboygan", 1964). She was the lead of the Broadway comedy
Any Wednesday (1964–66), which ran for 983 performances and won her a second Tony.
(1967)Dennis returned to the stage in a production of The Three Sisters'' (1966) with
Geraldine Page and
Kim Stanley that went to London and was filmed. Dennis' first lead role in a movie was in
Up the Down Staircase (1967), directed by
Robert Mulligan. In his review for
The New York Times,
Bosley Crowther cited her for "a vivid performance of emotional range and depth … engagingly natural, sensitive, literate and thoroughly moving." The film was a box-office success, as was
The Fox (1967), directed by
Mark Rydell, despite its controversial subject matter. In 1967 Dennis was voted the 18th biggest star in the US. Dennis briefly returned to Broadway to star in
Daphne in Cottage D (1967), which had a short run. She starred in
Sweet November (1968) as a woman who takes multiple lovers, and made a TV version of the play
A Hatful of Rain (1968). Dennis went to London to star in
A Touch of Love (1969), alternately titled
Thank You All Very Much in the USA, which flopped at the box office.
That Cold Day in the Park (1969), by
Robert Altman, did not fare much better.
The Out-of-Towners (1970), a
Neil Simon comedy with
Jack Lemmon, was a hit. Dennis guest starred in
Police Story ("Day of Terror... Night of Fear", 1978), and starred in the TV movies
Perfect Gentlemen (1979) (written by
Nora Ephron), and ''
Wilson's Reward (1981). On Broadway she briefly joined the cast of the long-running Same Time, Next Year''. She had a well-received part in
Alan Alda's
The Four Seasons (1981) and was in
The Supporting Cast (1981) on Broadway for
Gene Saks. She was in the stage production and film version of
Robert Altman's
Come Back to the Five and Dime, Jimmy Dean, Jimmy Dean (1982).
Later career In the mid- and late 1980s, Dennis acted less, owing to growing health problems. She appeared on TV in ''Young People's Specials
("The Trouble with Mother", 1985), The Love Boat ("Roommates/Heartbreaker/Out of the Blue", 1985), Alfred Hitchcock Presents ("Arthur, or the Gigolo", 1985) and The Equalizer ("Out of the Past", 1986). In motion pictures, she had supporting roles in a 1986 remake of Laughter in the Dark'', which was never completed,
Woody Allen's
Another Woman (1988), and the horror films
976-EVIL (1989) and
Parents (1989). Her final role was in the crime drama
The Indian Runner, filmed in 1990 and released in 1991. The movie marked
Sean Penn's debut as a film director. Actor
Viggo Mortensen, who played one of her two sons, wrote of the preparations for the movie and filming in the vicinity of
Omaha, Nebraska: ==Personal life==