She was born Corinne Anita Loos in Sisson, California, though the family lived in Etna, the second child of Richard Beers Loos (October 4, 1860-March 6, 1944) and Minnie Ellen Smith (September 16, 1859-October 9, 1938). Her brother and sister were H. Clifford Loos (October 23, 1882-August 29, 1960) and Gladys A. Loos (February 22, 1891-April 13, 1901). Her brother, Clifford, became a physician and was cofounder of Ross-Loos Medical Group in Los Angeles.
Her father was a journalist, humorist, editor and later screenwriter. The family moved to San Francisco in 1892, where R. Beers Loos, as he was known, ran a tabloid paper. Anita and her sister started acting on stage at an early age. In 1897, they performed in the San Francisco stock company production of Quo Vadis. In 1900, the family was enumerated on the Federal census in San Francisco. They later moved to San Diego, where they were enumerated in the census of 1910.
Read 1920s magazine articles about Anita Loos, presented free from Arizona State University.