Granger is a surname of English and French origin.
It is an occupational name for a farm bailiff.
[1] The farm bailiff oversaw the collection of rent and taxes from the barns and storehouses of the lord of the manor.
[1] This officer's Anglo-Norman title was grainger, and Old French grangier, which are both derived from the Late Latin granicarius (a derivative of granica, meaning "granary").
[1]