McGoohan was born in Astoria, Queens, New York City to Thomas McGoohan and Rose Fitzpatrick, who were living in the United States after emigrating from Ireland to look for work. Shortly after he was born, McGoohan's parents moved back to Mullaghmore, County Leitrim, Ireland and, seven years later, they moved to Sheffield, England. With the outbreak of the Second World War in 1939, McGoohan was evacuated to Loughborough, Leicestershire. There he attended Ratcliffe College, where he excelled in mathematics and boxing.

McGoohan left school aged sixteen and returned to Sheffield where he worked variously as a chicken farmer, a bank clerk and a lorry driver before getting a job as a stage manager at Sheffield Repertory Theatre. When one of the actors became ill, Patrick filled in, launching his acting career. He fell for an actress named Joan Drummond, the woman to whom he reportedly writes love notes every day.

They are still considered one of show business's happiest couples. They were married between a rehearsal of The Taming of the Shrew and an evening performance on May 19, 1951. They have three daughters, Catherine (b. 1952), Anne (b. 1959) and Frances (b 1960).

On a few occasions McGoohan has played the part of a priest. In 1955, McGoohan starred in a West End production of a play called Serious Charge, in the role of a priest accused of being gay. Orson Welles was so impressed by McGoohan's stage presence ("intimidated," Welles said later), Welles cast him as Starbuck in his York theatre production of Moby Dick Rehearsed.

While working as a stand-in during actress screen tests, McGoohan was signed to a contract with the Rank Organisation, the largest European Production Company between 1930 and 1960. The producers may have been more interested in capitalizing on his boxing skill and appearance than his acting ability, casting him as the conniving bad boy in such films as the gritty Hell Drivers and the steamy potboiler The Gypsy and the Gentleman, and after a few films and some clashes with the management, the contract was dissolved.

Free of the contract, he did some TV work and continued on the stage in his favourite role, Ibsen's Brand, for which he received an award, and soon producer Lew Grade approached him about another contract, this time for a TV series. Having learned from his experience as a product of the Rank Organisation, McGoohan insisted on several conditions before agreeing to do the spy show Danger Man: all the fistfights should be different, the character would always use his brain before using a gun, and, much to the horror of the executives, no kissing.

They hired him anyway. The first series, half-hour shows about a spy named John Drake geared toward an American audience, did fairly well, but not as well as they hoped in the US. It lasted only one year. After the series was over, one interviewer asked McGoohan if he would have liked the series to continue, to which he replied, "I would rather do twenty TV series than go through what I went through under that Rank contract I signed a few years ago for which I blame no one but myself."

Danger Man was rerun in several countries, and gained in cult status worldwide. McGoohan spent some time working for Disney on The Three Lives of Thomasina and The Scarecrow of Romney Marsh. McGoohan had already turned down the roles of James Bond and Simon Templar (The Saint) when Lew Grade asked him if he would like to give John Drake another try.

This time, McGoohan had even more say about the series; it was expanded to an hour and the writing was changed to allow McGoohan more acting range. The series' popularity exploded. McGoohan became the highest paid actor in England and it lasted almost three more seasons.

During the fourth season filming, after shooting the first two episodes in colour, McGoohan told Lew Grade he was going to quit. Grade asked if he would at least work on "something" for him, and McGoohan gave him a run-down of what would later be called a miniseries about a secret agent who resigns suddenly and wakes up to find himself in a prison disguised as a holiday resort.

Grade asked for a budget, McGoohan had one ready, and they made a deal over a handshake early on a Saturday morning to produce The Prisoner. McGoohan not only produced, he also wrote, directed and starred in the show.

He used two pseudonyms: writing "Free for All" as Paddy Fitz and directing "Many Happy Returns" and "A Change of Mind" as Joseph Serf. He also wrote "Once Upon A Time" and "Fall Out" using his own name. The seven episodes were increased to seventeen.