The word itself comes from the French "portmanteau", meaning "cloakroom" or "coat rack".
The term was popularized by Lewis Carroll in his book "Through the Looking-Glass" where he describes the word as "a kind of bag" that holds two different things.
While it's not directly named after a specific person, the idea of a portmanteau as a container for multiple things likely draws inspiration from the various types of traveling bags and trunks that existed in the Victorian era.