John Mitchell (1870-1919), was born in Braidwood, Ill. He began working as a miner in 1882 and worked in the Illinois coalfields as well as, briefly, in Colorado, New Mexico, and Wyoming. He also read law for a year during the 1880s. In 1885 he joined KOL National Trade Assembly 135.

A member of the Spring Valley, Ill., local of the United Mine Workers of America in the early 1890s, he was elected secretary-treasurer of the northern Illinois subdistrict of United Mine Workers' District 12 (Illinois) in 1895, became the lobbyist for District 12 in 1896, and was elected a member of the union's Illinois state executive board and appointed a national organizer in 1897. Mitchell was elected vice-president of the United Mine Workers in 1898, became acting president later that year, and served as the
union's president until 1908. He was also an AFL vice-president (1899-1913).

A founder of the National Civic Federation in 1900, he served as a member of its executive committee (1901, 1903-10), Industrial Department (1901-2), and executive council (1904-10). He was later a member of the New York State Workmen's Compensation Commission (1914-15) and chairman of the New York State Industrial Commission (1915-19).