Nesbitt made her debut in London in the stage revival of
Arthur Wing Pinero's
The Cabinet Minister (1910). She acted in many plays after that. In 1911, she joined the Irish Players, went to the United States and debuted on Broadway in
The Well of the Saints. She also was in the cast of
John Millington Synge's
The Playboy of the Western World with the Irish Players when the whole cast was pelted with fruits and vegetables by the offended Irish American Catholic audience. Nesbitt returned to the United States and appeared on Broadway in
Quinneys (1915) and
John Galsworthy's
Justice (1916) as
John Barrymore's leading lady in his first dramatic stage role. After five other plays there, she returned to England. For the rest of the decade she performed in London; her roles included the title role in a revival of
John Webster's
The Duchess of Malfi. Her film debut was in the
silent A Star Over Night (1919). She then performed in
The Faithful Heart (1922). She did not appear in a film again until 1930, when she played the role of Anne Lymes in
Canaries Sometimes Sing, which was an early
talkie. In 1932, she appeared in
The Frightened Lady. She appeared in the 1938 film version of
Pygmalion as "a lady" who attends the Embassy ball. In the opening credits her first name was spelled as "Kathleen", but as "Cathleen" at the end of the film. She played the role of Lady Macbeth in the 1945 16 minute short film "
Famous Scenes From Shakespeare No 2: Macbeth." She played the part of Mother in the 1949 BBC TV remake of the drama film
Elizabeth of Ladymead, and Julia in the August premiere of
T.S. Eliot's play
The Cocktail Party. Nesbitt's first
Hollywood film was
Three Coins in the Fountain (1954), in which she played the character role of La Principessa. This was followed that same year by
Black Widow, in which she played Lucia Colletti. She was
Cary Grant's Grandmother Janou in 1957's
An Affair to Remember (though she was only 16 years older than Grant) and, the following year, was part of the ensemble cast of
Separate Tables. She also appeared in
The Parent Trap (1961), and
Promise Her Anything (1965). '' in 1952 Other Broadway appearances included Aunt Alicia in the original
Anita Loos adaptation of
Gigi (1951),
Sabrina Fair (1953), and
Anastasia (1954). In 1956, she played Mrs. Higgins in
My Fair Lady starring
Rex Harrison. Nesbitt reprised the role in 1981, in her 90s, in a Broadway revival, opposite Harrison, who was in his 70s. Nesbitt portrayed Agatha Morley, the mother of a Congressman (played by
William Windom) and mother-in-law to his former governess (played by
Inger Stevens), in the TV series ''
The Farmer's Daughter from 1963 to 1966. She guest starred on such shows as The United States Steel Hour; Wagon Train; Naked City, Dr. Kildare and Upstairs, Downstairs'' (as
Rachel Gurney's mother, Mabel, Countess of Southwold). In 1969, Nesbitt played
Richard Burton's mother in the film
Staircase and again in
Villain two years later. She had a small but memorable role as an elderly drug addict in
French Connection II (1975) alongside
Gene Hackman. Her next film was
Alfred Hitchcock's
Family Plot (1976), in which she played Julia Rainbird. She then appeared as the grandmother in
Julia (1977). Her final film was
Never Never Land (1980) as Edith Forbes. ==Personal life==