When Leonard Cookston was born in October 1824, in Hamilton, Tennessee, United States, his father, Joseph A Cookson, was 26 and his mother, Christina Vandegriff, was 19. He married Martha E. Killian about 1846, in Hamilton, Tennessee, United States. They were the parents of at least 5 sons and 7 daughters. He lived in Tennessee, United States in 1870 and District 3, Marion, Tennessee, United States in 1880. He registered for military service in 1863. He died on 23 January 1892, in Marion, Tennessee, United States, at the age of 67, and was buried in Teague Cemetery, Powells Crossroads, Marion, Tennessee, United States.