[Michael probably moved into the Prostitution business when the Corleone's went out west. After all it was not illegal out there.
Don Cardi
Yes, and that constitutes a marvelous little example of Michael's definition of "legitimate." Throughout his life, he attempted to be "legitimate," but on terms that he defined. His father abhorred prostitution. But, since prostitution was legal in Nevada, and Michael was a "legitimate" businessman, he could own a brothel and still consider himself "legitimate."