McGoohan is the son of Rose (Fitzpatrick) and Thomas McGoohan, who are living in the United States after emigrating from Ireland to seek work. He is brought up as a Catholic. Shortly after he is born, his parents move back to Mullaghmore, County Leitrim. Seven years later they emigrate to Sheffield, England.
McGoohan attends St. Vincent’s School and De La Salle College in Sheffield. During World War II, he is evacuated to Loughborough, Leicestershire. There he attends Ratcliffe College, where he excels in mathematics and boxing. He leaves school at the age of 16 and returns to Sheffield, where he works 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 becomes ill, McGoohan is substituted for him, launching his acting career.
McGoohan is most closely identified with two 1960s British television series, Danger Man and The Prisoner. The espionage drama Danger Man, which runs in the United States as Secret Agent, runs for 86 episodes during 1960–1961 and 1964–1967. The cult hit The Prisoner runs for 17 episodes in 1967–1968.
In Danger Man McGoohan puts a new spin on the secret agent formula by refusing to allow his character, John Drake, to carry a gun or indulge in sexual dalliances. The show’s success makes him Britain’s highest-paid TV actor.
McGoohan is one of several actors considered for the role of James Bond in Dr. No. While McGoohan turns down the role on moral grounds, the success of the Bond films is generally cited as the reason for Danger Man being revived in 1964. He is later considered for the Bond role in Live and Let Die, but again turns it down.
The success of Danger Man provides McGoohan the leverage he needs to produce The Prisoner, an allegorical Kafkaesque series in which he portrays Number Six, an unnamed agent, thought by many to represent Drake, who angrily resigns and is then held captive in a superficially banal place called The Village, where the mysterious unseen Number One, the ever-changing Number Two, and others try to overcome the fiercely individualistic Number Six’s escape attempts and pry information from him.
McGoohan’s later works include the short-lived medical mystery series Rafferty (1977), such films as Ice Station Zebra (1968), Escape from Alcatraz (1979), and Braveheart (1995), the Broadway spy drama Pack of Lies (1985), and a record four guest-villain appearances on the American detective series Columbo, two of which earned him Emmy Awards. He also directs and writes several episodes of The Prisoner and Columbo. One of his last roles is as Number Six in a 2000 episode of the animated TV comedy The Simpsons.