Leon Ashby Dickson was born in Portland, Maine, on October 17, 1913. He was the eleventh Black student to attend Bowdoin. He graduated from Bowdoin cum laude and was a member of Phi Beta Kappa. While at Bowdoin, he was active in music and a member of the track squad. Following Bowdoin, he studied medicine at Howard University, graduating in 1939. He was a physician in Washington, DC and later Detroit, Michigan. During World War II, Dickson served in the Medical Corps of the United States Army, and from 1946-1947 in the Veterans Administration in Tuskegee, Alabama.
