Katy Leary was born to Irish immigrants in Elmira, New York. Her sister Mary was a maid in the Langdon family house. Livy hired Katy in 1880, bringing her to live in Hartford; from then until 1910 Katy lived and traveled with the family (except in 1895–96, when she remained in Elmira with Susy and Jean while SLC, Livy, and Clara went around the world). After Livy’s death in 1904 she became SLC’s housekeeper. For some years after SLC’s death, she ran a boarding house in New York City. Her memoirs, written with the assistance of Mary Lawton, were published as A Lifetime with Mark Twain (1925).