Harry L. Mitchell, one of the founders of the Southern Tenant Farmers Union and president of the National Farm Labor Union, was born near Halls, the son of James Y. Mitchell, a tenant farmer and Baptist preacher. Mitchell graduated from Halls High School in 1924 and shortly thereafter became a sharecropper near Ripley, Lauderdale County. He married Lyndell Cannack, a teacher, on December 26, 1926, and operated a dry-cleaning business in Tyronza, Arkansas, from 1927 to 1934. Mitchell married a second time, in 1951, to Dorothy Dowe.
With seventeen others, Mitchell founded the Southern Tenant Farmers Union (STFU) in 1934, serving as its executive secretary from 1934 to 1939 and from 1941 to 1944. Mitchell organized tenant farmers during 1934 and led strikes in Arkansas and Tennessee in early 1935. These brought national attention to the STFU, and by 1937 some thirty thousand tenant farmers and sharecroppers had joined. Mitchell lost faith in orthodox union tactics after the failure of several strikes. He emphasized the role of the STFU as a special interest group. Mitchell affiliated with the politically sensitized Congress of Industrial Organizations and merged, reluctantly, with the Communist-led United Cannery, Agricultural, Packing and Allied Workers of America (UCAPAWA) in 1937. After numerous quarrels with UCAPAWA president Donald J. Henderson over STFU autonomy, Mitchell left the UCAPAWA in 1939. He was elected president of the STFU in 1944, and led the union into the American Federation of Labor (AFL) under the National Farm Labor Union (NFLU). He served as president of the NFLU from 1945 to 1955 and its successor, the National Agricultural Workers Union (NAWU), AFL-CIO, from 1955 to 1960.
Although the STFU failed to accomplish its goals in the 1930s, Mitchell and others showed considerable personal courage as they stood up to local planters. Through their efforts, the STFU gained national attention for the problems of sharecroppers and tenants and won occasional economic victories.