Clint Eastwood's contract for Rawhide (1959) prohibited him from making movies in the United States while on break from the series. However, the contract did allow him to accept movie assignments in Europe.
Since all of the footage was filmed silently, Clint Eastwood did not add his voice to the soundtrack until 1967, when the movie was prepared for U.S. release.
Sergio Leone warmed to Clint Eastwood very quickly and joked that he had only two expressions: with hat or without hat.
Originally called "The Magnificent Stranger," the title wasn't changed to "A Fistful of Dollars" until almost three days before the movie premiered in theaters. In fact, nobody had bothered to inform Clint Eastwood of the change, and as a result, Eastwood remained virtually unaware of the positive buzz surrounding the movie until an agent pointed it out to him in a Variety Magazine article three weeks later.
Clint Eastwood recalled, "I've never been to Italy. I've never been to Spain. I've never been to Germany. I've never been to any of the countries (co-producing) this film. The worst I can come out of this is a nice little trip. I'll go over there and learn some stuff. I'll see how other people make films in other countries."