The store was founded by Steven Miller and Stephen Oppenhiem in 1976, when they were selling junk from a pickup truck. In 1978, they rented a 2000 square foot space on SE 12th, and moved to their current location in 1990.
In July 2013, concerns were raised over poor treatment of two cockatiels for sale at Hippo Hardware. A PortlandWiki editor called for a boycott. There has been no proof or evidence provided concerning the treatment of the cockatiels.