For many years this film only existed in murky 9.5mm dupes on the black market. In March 1973, at a screening of this film at George Eastman House, archivist James Card said that Henri Langlois and his staff at the Cinematheque Francais discovered a copy of it in 1968 among other miscellaneous cans of film marked "l'inconnu" (films "unknown" due to missing titles, etc.).
Joan Crawford always considered The Unknown (1927) a big turning point for her. She said it wasn't until working with Lon Chaney in this film that she learned the difference between standing in front of a camera and acting in front of a camera. She said that was all due to Lon Chaney and his intense concentration, and after that experience she said she worked much harder to become a better actress.