Kathryn Josephine King was born on March 17, 1895 in Attyguddane, County Galway, Ireland. Her parents were Peter King and Bridget Hefferman of Ireland.

Kathryn emigrated from Ireland in 1920. She declared her desire to become a Naturalized Citizen in 1927. According to a Passenger List from her return trip from Ireland in 1937, she had become a Naturalized Citizen in 1928.

At the time of the 1930 census, "Catherine" King, 31, lived on Ellsworth Avenue, Pittsburgh, with Nellie King, 30, and Sarah King, 38. All were Registered Nurses. Helen Agnes "Nellie" King graduated from the Mercy Hospital School of Nursing in 1915. In other census records, Sarah was not listed as a nurse.

In the 1940 census, "Katherine J. King", 42, was a Public Health Department Nurse. She lived on Kirtland Avenue with her sister, Sara J., 37.

From a list of Pennsylvania Registered Nurses, 1940-1941, published by the Pennsylvania State Board of Nurse Examiners: "Katherine King, 613 Kirtland St., Pittsburgh."

During World War II, Kathryn served in the Army Nurse Corps. She was a Second Lieutenant and served from April 5, 1943 until February 17, 1946.

Kathryn died on March 21, 1986 in Pittsburgh. She is buried at Calvary Cemetery, Pittsburgh.