The Prisoner was created while Patrick McGoohan and George Markstein were working together on the espionage show Danger Man, though there is no official 'created by' credit and the exact division of creative contribution between the two remains disputed.

Part of Markstein's inspiration came from his research into World War II, where he discovered Inverlair Lodge, a resort-like prison near Inverness in Scotland used to incarcerate people, which he suggested could be the fate of Danger Man's John Drake after a sudden resignation.

The Welsh village of Portmeirion, which became the Village's main filming location, had already caught McGoohan's eye years earlier when exteriors for a 1960 Danger Man episode called 'View from the Villa' were filmed there.

McGoohan wrote a forty-page 'show Bible' detailing the Village's history, telephone system, sewerage, food, transport and boundaries for the writers to follow.

McGoohan wrote the episode 'Free for All' under the pen name Paddy Fitz and directed 'Many Happy Returns' and 'A Change of Mind' under the pseudonym Joseph Serf, a surname ironically meaning a peasant controlled by a feudal master.

McGoohan stated in a 1985 interview that Number Six was not meant to be the same character as John Drake from Danger Man, and that he had originally wanted another actor to play the role, though some crew members who moved over from Danger Man believed it was a direct continuation.

At the request of Portmeirion's architect Clough Williams-Ellis, the identity of the main filming location was kept secret until the final episode's closing credits, which finally revealed it as 'The Hotel Portmeirion, Penrhyndeudraeth, North Wales'.

Filming for a key opening-credits sequence and exteriors for three episodes took place at 1 Buckingham Place in Westminster, then a private residence used as Number Six's home, which now houses the Royal Warrant Holders Association.

Although most British television at the time was broadcast in black and white, The Prisoner was filmed in colour specifically to appeal to the American market.

McGoohan originally wanted to produce only seven episodes, but Lew Grade insisted on more so the show could be sold to CBS; accounts differ on whether Grade requested 26 or 36 episodes before McGoohan settled on 17.

The ambiguous, open-ended finale generated such controversy and outrage from viewers that McGoohan reportedly had to go into hiding for a while afterward.

The series has influenced and been referenced by later works such as the film The Truman Show and the TV shows Lost and The X-Files, with The X-Files' producer calling it 'the Gone with the Wind of its genre.'