After touring the country in
Blossom Time, she was cast as Grusinskaia in the Broadway adaptation of
Vicki Baum's novel
Grand Hotel. An enormous success, the play, which opened in 1930, was later filmed with
Greta Garbo in the part created by Leontovich. After
Grand Hotel, Leontovich was given the role of Lily Garland (aka Mildred Plotka) in
Twentieth Century, a comedy by
Ben Hecht and
Charles MacArthur. She played the role from December 29, 1932, until May 20, 1933. She also played the Archduchess Tatiana in
Tovarich, a comedy about a pair of Russian aristocrats who survive in Paris by going into domestic service. It was in this play that she made a highly successful London debut at the
Lyric Theatre in 1935, with
Cedric Hardwicke as her co-star. During World War II, she appeared on Broadway in
Dark Eyes, a comedy she wrote with
Elena Miramova about three Russian exiles in New York. The play was produced in London after the war with Eugenia Delarova and
Irina Baronova. In 1936, she played
Shakespeare's Cleopatra at the
New Theatre, returning to London in 1947 as a female Russian general in a farce which she co-wrote,
Caviar to the General, which temporarily displaced
Phyllis Dixey at the
Whitehall. A year later, she moved to Los Angeles, where for the next five years she had her own theatre, The Stage, where she both produced and performed. In 1954, she created the role of the Dowager Empress in the play
Anastasia on Broadway. (The role was played by
Helen Hayes in
the film version.) In 1972, she adapted
Anna Karenina for off-Broadway, calling it
Anna K. and appearing in it with success. Leontovich made a handful of films. For most of her long professional life, she was identified with the stage. For seven years in the 1960s, she was artist in residence at the
Goodman Theater in Chicago. She taught acting in California and New York. ==Personal life and death==