The position of M is appointed to a different person as time goes on and the current M either dies or retires. Four different people (three men and one woman) have been given this position in James Bond's career, and none of these people have been given official names.
M is the creation of famous British writer Ian Flemming. He/She first appeared in movies in Dr. No, although he/she was featured in the non-Eon TV movie adaptation of Casino Royale in 1954. M first appeared in a James Bond comic book in 1965 in an issue of "James Bond Agent 007".