From Wikipedia, the free encyclopedia Dennis W. Day (July 12, 1942 – c. July 17, 2018) was an American actor, singer, dancer and theater director, best known as one of the original cast members of The Mickey Mouse Club. After ending his career as a child actor, he went on to work as a theater director before relocating to Oregon in the 1980s. Day disappeared in July 2018 and was found dead several months later. A roommate was charged with his death in 2019.