Rex Ashlock was born in Spokane Washington in 1918. He was the oldest of three children in a family that encouraged creativity. He attended the University of Washington in Seattle briefly prior to moving to California in the late 1930s'.
In San Francisco he studied at The California School of Fine Arts under David Park. Later he taught there as well. Among his students was Nathan Olivera. He also taught at the California College of Arts and Crafts and at Berkeley Evening Adult School.
In 1957 he moved to New York City where he remained until 1980. During this period he showed his work in local galleries and taught at the school at The Museum of Modern Art before starting his own school in the 1970s. While in New York he produced the greater part of the body of his work in paintings and sculpture.
In 1980 he left New York and returned to Spokane Washington where he remained until 1984. During this time he continued to work but the scale of projects was reduced.
When he left Spokane he returned to San Francisco where he continued to work on smaller projects until his death in December 1999.