Katharine Anthony was born in Roseville, Logan County, Arkansas, the third daughter of Ernest Augustus Anthony 1846-1904 and Susan Jane Cathey 1845-1917. Her father was a grocer and later a police officer.

She studied at Peabody College for Teachers in Nashville, the Universities of Heidelberg and Freiburg, and the University of Chicago. She received a Ph.B degree from Chicago in 1905 and taught at Wellesley College in 1907. She became a public school teacher by 1910 and worked at that time in Fort Smith, Sebastian County, Arkansas. She moved from Arkansas perhaps because her mother had died in 1917, and by 1920 she was living in Manhattan with her life-partner Elisabeth Irwin (1880—1942), the founder of the Little Red School House.

Her book Catherine the Great was positively reviewed in the New York Times (Dec 20, 1925, pg BR8), which notes that Miss Anthony had, apparently for the first time, access to all of Catherine's private memoirs. Her book Marie Antoinette was called a "...fresh and original life of Marie ..." by the New York Times reviewer (Jan 29, 1933 pg BR5).

Her books Catherine the Great and Queen Elizabeth each sold more than 100,000 copies.

She died at St. Vincent's Hospital, two weeks after having a heart attack. Her obituary appeared in the New York Times on Nov 22, 1965 (pg 37). She was survived by a sister, Mrs. Blanche Brown of Berkeley, California. Her funeral was in New York City, and burial at Gaylordsville, Connecticut where she had a summer home.