On her father's side, Agnes was the granddaughter of playwrights Henry Churchill de Mille and Matilda Beatrice deMille.

[1] She had a love for acting and originally wanted to be an actress, but was told that she was "not pretty enough", so she turned her attention to dance.

Classical ballet was the most widely known dance form at this time, and de Mille's apparent lack of ability limited her opportunities.

One of de Mille's early jobs, thanks to her father's connections, was choreographing Cecil B. DeMille's film Cleopatra (1934).

Her uncle always deferred to Prinz, even after agreeing to his niece's dances in advance, and Agnes de Mille left the film.

One of de Mille's first pieces was Black Ritual (Obeah), which she began choreographing for the newly formed Ballet Theatre's first season.

Besides Rodeo, two other de Mille ballets are performed regularly, Three Virgins and a Devil (1934) adapted from a tale by Giovanni Boccaccio, and Fall River Legend (1948) based on the life of Lizzie Borden.

The dream ballet, in which dancers Marc Platt, Katherine Sergava, and George Church doubled for the leading actors, successfully integrated dance into the musical's plot.

This production is widely known for this innovative idea and is credited for starting de Mille's fame as a choreographer, both for Broadway and in the dance industry.

[7] De Mille went on to choreograph over a dozen other musicals, most notably Bloomer Girl (1944), which presented her feelings of loneliness as a woman who saw her husband leave to serve for the army, Carousel (1945), Allegro (1947, director as well as choreographer), Brigadoon (1947, for which she was co-recipient of the inaugural Tony Award for Best Choreography), Gentlemen Prefer Blondes (1949), Paint Your Wagon (1951), The Girl in Pink Tights (1954), Goldilocks (1957), and 110 in the Shade (1963).

De Mille revolutionized musical theatre by creating choreography that not only conveyed the emotional dimensions of the characters but enhanced the plot.

De Mille regularly worked with a recognizable core group of dancers, including Virginia Bosler (Doris), Gemze de Lappe, Lidija Franklin, Jean Houloose, Dania Krupska, Bambi Linn, Joan McCracken, James Mitchell, Mavis Ray, and, at American Ballet Theatre, Sallie Wilson.

She was interviewed in the television documentary series Hollywood: A Celebration of the American Silent Film (1980)[9] primarily discussing the work of her uncle Cecil B. DeMille.

Agnes de Mille appears in a wheelchair in Frederick Wiseman's 1995 film Ballet rehearsing her final piece, "The Other."

The bulk of the papers date from 1914 to 1960 and focus on both personal and professional aspects of de Mille's life.