Harry Houdini was born Eric Weiss, but that name would not do justice to his magical ambitions. The origin of “Harry” was simple — he’d been called “Ehrie” as a kid, so he just Americanized the old nickname. “Houdini” was a tribute to one of the pioneers of modern magic, Jean Eugene Robert-Houdin. Robert-Houdin was a watchmaker who opened his own magic theater in 1845. He is widely credited with being the first to perform in black tie rather than fancy gowns, thus making magic a little more mainstream.
Oddly enough, Houdini turned against his magical namesake write a book called later in life The unmasking of Robert-Houdin in which he criticized Robert-Houdin for stealing other magicians’ tricks.