The Southern Tenant Farmers' Union was founded in 1934, in Tyronza, Arkansas, a rural town in northeast Arkansas. The region up until the 1930s was fertile and impoverished, consisting primarily of cotton plantations own by a small number of land owners. Sharecroppers, tenant farmers, and agricultural laborers worked the land. Sharecroppers were provided seed, tools, a shack to live in and credit to buy food and clothing. They turned over half their crop to the landowner. Tenant farmers provided their own tools and seed, turning over one third of their crop to the landowner. Agricultural laborers worked the landowners' land for small wages.

The New Deal agricultural subsidy programs redistributed income towards the landowners, at the expense of the sharecroppers and laborers working the land. With this miscarriage of policy as their impetus, H.L. Mitchell and Henry Clay East, two self-taught socialists, who ran a laundry and filing station respectively, in Tyronza, began talking up socialist alternatives to the agricultural system in operation in much of the Arkansas delta. The first meeting of the STFU, on July 13th 1934, was attended by an interracial assembly of eighteen local sharecroppers and tenant farmers.

Despite extreme persecution by landowners and deputy sheriffs the STFU quickly developed locals in communities throughout the delta region and beyond. The STFU numbered 31,000 members at its peak in 1938, and parleyed support from socialist leader Norman Thomas, Eleanor Roosevelt, Rheinhold Niebuhr, Gardner Jackson (working in 1934 for the Department of Agriculture), and others to obtain the ear of federal agricultural policy makers.

Enduring shootings, beating and near-lynchings, the STFU obtained a great deal of press coverage. A "March of Time" newsreel was made in 1935 about sharecroppers. Several agricultural strikes and two roadside encampments-highlighting the plight of agricultural workers-garnered national press coverage. State commissions were established to relieve the plight of sharecroppers in Arkansas and neighboring Missouri and federal legislation was passed: the STFU influenced the creations of programs to underwrite loans for sharecroppers to buy their own farms, and to build emergency housing for agricultural laborers.

The STFU is also memorable for the quasi-religious character the movement assumed. The union had its own anthems and fighting songs ("Roll the Union On," was composed by STFU member John Handcox). It had elaborate rituals: "The Ceremony of the Land," and a string-tying initiation ceremony. Principles of racial equality were espoused from the beginning of the STFU, making it one of the first interracial organizations of working people to function in the southern United States.