King was born on April 19, 1872 in Waterford, Pennsylvania. From 1889 to 1893 he attended Battle Creek College, and then attended the University of Michigan, Ann Arbor, graduating in 1896. In 1902 he founded and edited the Morning Sun in Denison, Texas, while in 1905-06 he was editor of the "Independent Voter" in Toledo, Ohio. In 1912 he married the suffragist, Dr. Cora Smith Eaton.
Having functioned during 1908-10 as Field Secretary of the Ohio Direct Legislation League, King served between 1933 and 1958 as Director of the National Popular Government League. Between 1935 to 1944, he worked concurrently as a special consultant to the Rural Electrification Administration. In 1926 he married Bertha Hale White, the former Executive Secretary of the Socialist Party of America. He died on July 4, 1958 in Washington, DC.