Katherine Heilner MacDonald was born in Brooklyn, New York on November 30, 1882, to Rear Admiral Louis Cass Heilner, U.S. Navy, and Susan Coffee Heilner. A printmaker, painter and teacher, MacDonald studied with Arthur Dow at the Federal Art School in Minneapolis and the Pratt Institute in New York. The Pratt Institute Monthly under the heading Alumni Notes has her listed as residing at 134 Dean Street in New York City in 1902. Miss Katherine Heilner was listed as one of the "Navy girls" who attended the May 1910 launch of the battleship Florida. Her father died on January 25, 1912, and a few months later on March 21^st, she married Lieutenant Ray Strath MacDonald but was widowed five weeks later. She moved to Coronado, California in 1932 and then to the San Francisco Bay Area in 1945 where she settled in Burlingame. Katherine worked primarily in watercolor and charcoal until 1927, when she began to work in color linoleum block prints.

She was a member of the Art Guild and the Fine Art Society of San Diego. Her work was included in the California-Pacific International Exposition in San Diego in 1935, and the Golden Gate International Exposition in San Francisco in 1939.

Katherine Heilner MacDonald died on November 28, 1967, in Burlingame, California.