Yes, he has seven names - the reason being that his father promised all the men who he owed money to that he would name his unborn child (Kiefer) after them! There was an interview with Kiefer about this in Empire a few issues ago. Give me a couple of days and I'll dig it out...
Kiefer William Frederick Dempsey George Rufus Sutherland. I don't know about the story behind the other names but Kiefer comes from Warren Kiefer, pen name of Lorenzo Sabatini. Sabatini directed Castello dei morti vivi, Il (1964) [aka Castle of the Living Dead (1964)], in which Donald Sutherland made his theatrical film debut. Courtesy of imdb.com