|Previous Occupation||Pittsburgh Police Detective|
|Previous Partner||Lou Destefano|
|Objects Owned||The Key, The Bus Ticket(loaned), The Comb, The Wedding Photo|
|Debut||The Key and the Clock|
Joe Miller was a detective with the Pittsburgh Police Department, and the main character of the TV series. After his daughter Anna Miller disappeared into The Room, he attempts to learn as much as he can about the Objects and their special powers. Initially, he hopes that the mythical Prime Object can return his lost daughter, and after being tricked by the Weasel into stealing the Clock from Karl Kreutzfeld, he abandons the Weasel and the Prime Object theory. He learns of the Occupant after using the Polaroid on the site of the ruined Sunshine Motel; seeing the Room as it was before the Event renews his hope that the Occupant can return his lost daughter.
Tracking down the Occupant, he discovers that the only way he can recover Anna from the endless iterations of the Lost Room is to shoot the Occupant within the Lost Room and take his place; Joe does so at the Occupant's request, and though deeply disturbed and unwilling, he does so in order to get his daughter back. In the aftermath, while he has become the new Occupant (called by some Object-Seekers the 'Joe Miller Object'), he is not erased from history. He willingly gives up The Key and places it in the room and closes the door behind him as the story ends.