From the experts:
Kiefer is a strong occupational surname associated with "24" star Kiefer Sutherland, but one that could well join the other 'er' surnames currently in favor. Keifer is a German surname transferred to first name use, derived from two old Germanic words, kien and forhe, both of which mean "pine tree."
Kiefer Sutherland, the son of actor Donald Sutherland, was named for director Warren Kiefer, who gave Donald Sutherland his first movie role. Donald was a firm believer in honoring valued friends and mentors--his other sons are named Roeg, Rossif and Angus. Kiefer Sutherland's full name is Kiefer William Frederick Dempsey George Rufus.
Another possible cultural namesake is the esteemed German artist Anselm Kiefer.