Eddy Louiss was born Edouard Louise on May 2, 1941 in Paris, France. Born into a musical family, his father was a trumpet player, and he studied several musical instruments, including trumpet and piano.
In his early teenage years Louiss played in his father's band. In the early 60s he was playing piano in various Paris nightclubs and continuing with his studies. He also sang with the French vocal group Double Six, other members of which included Roger Guérin, Ward Swingle and Christiane Legrand, the sister of Michel Legrand.
Adding the organ to his array of instrumental ability, Louiss played with various jazzmen in the 60s, among them Johnny Griffin, Art Taylor , Dizzy Gillespie, and Stan Getz. In the late 60s he was with a trio led by Kenny Clarke and he also recorded with Barney Kessell. Louiss continued to play extensively throughout Europe during the 70s and into the 80s when he formed an adventurous big band, Multicolor Feeling. In the 90s he was also heard in duo with Michel Petrucciani.