Usually called La Leyenda Viviente(the living legend), Mil was born in San Luis Potosi, Mexico. Some bios list his birth year 1938, 1941 or 1942 or even 1944, but the most common date is 1942.
The character of Mil Mascaras was announced before his debut. The gimmick is a creation of "El Rey Midas de la Lucha Libre", Valente Perez, and in fact, the first appearances of Mil Mascaras were not by the current (and long time) man under the mask. Valente came up with the idea of of Mil wearing a different mask for each presentation, and this has sometime expanded to him wearing two masks for matches, throwing one to the crowd.
Mil made his debut as Ricardo Duran, and was trained by Diablo Velasco. He was the first Mexican and the first masked man who appeared in the Madison Square Garden, and he's famous in Japan.
One of Mil's first feud matches was against Benny Galant, who Mil beat for his hair. Mil has had notables feuds Canek, Gran Markus Jr. and El Halcón. Mil's popularity has also increased due to his movies.
He's still wrestling today.
Mil's real name has appeared in the credits of movies he's produced, and is not a great secret. However, as he's not lost his mask, we've chosen not to list it here.
Filmography
Mil Máscaras (1966), 1st appearance and origin of Mil Mascaras (the only B&W film in the series)