He was born in Oakley, Hinds County, Mississippi, the son of Jesse and Jerusha Finnell.
[3] He made a series of studies and published reports outlining more efficient methods of utilizing water in the semi-arid southern Great Plains region, such as terracing and contour plowing.
By May 1936, nearly 40,000 farmers had adopted his methods, "and 5.5 million acres were under new terraced and contour-listed cultivation.
At the end of 1937, despite the persistent dust storms, the amount of dangerously eroded land had been reduced by more than half.
Finnell continued to study wind erosion and land use for the government until his retirement in 1959.