The third oldest of twelve children (eleven of whom lived to adulthood), Gilbreth grew up in Montclair, New Jersey, in an unconventional household.

[2] Frank Gilbreth suffered a fatal heart attack on the eve of Ernestine's high school graduation, which delayed Ernestine's college plans by a year, as the family's finances dictated that her mother return to work immediately, carrying on the work she and her husband did as industrial/management consultants.

[2] Gilbreth Carey would go on to publish three more novels during the 1950s, all semi-autobiographical: Jumping Jupiter (1952), Rings around Us (1956), an account of the events that happened from the night she met her future husband, to the night the two watched their daughter dance the Charleston as a high school freshman,[3] and Giddy Moment (1958), though none of them would come close to the popularity of Cheaper by the Dozen.

From the 1970s until shortly before her death in 2006, Carey researched and wrote multiple drafts of various versions of biographical treatments of both her parents and her mother.

[2] During the 1950s and early 1960s, Carey enjoyed a moderately successful career as a speaker, especially for women's clubs and local libraries.

Ernestine Gilbreth Carey was also an active alumna, holding office in her local Smith College clubs both on Long Island and in Phoenix.