Leon James Downing was born on July 1, 1901 in Lenawee County, Michigan. He was the son of Charles James and Martha (Carmen) Downing. He was the twin brother of Leland Downing.

On April 4, 1903, Leon died at the age of 21 months in Ridgeway Township, Lenawee County, Michigan. He is buried in Ridgeway Cemetery in Ridgeway Township.