Johnson was educated at the Jesuit independent school Stonyhurst College, and at Magdalen College, Oxford. He first came to prominence in the 1950s as a journalist writing for and later editing the New Statesman magazine. A prolific writer, Johnson has written over 40 books and contributed to numerous magazines and newspapers. His sons include the journalist Daniel Johnson, founder of Standpoint, and the businessman Luke Johnson, former chairman of Channel 4.
Johnson was born in Manchester. His father, William Aloysius Johnson, was an artist and Principal of the Art School in Burslem, Stoke-on-Trent, Staffordshire. At Stonyhurst, Johnson received an education grounded in the Jesuit method, which he preferred over the more secularized curriculum of Oxford. One of his tutors at Oxford was the historian A. J. P. Taylor.
After graduating with a second-class honours degree, Johnson performed his national service in the Army, joining the King's Royal Rifle Corps and then the Royal Army Educational Corps, where he was commissioned as a Captain (acting) based mainly in Gibraltar. Here he saw the "grim misery and cruelty of the Franco regime". Johnson's military record helped the Paris periodical Realités hire him, where he was assistant editor from 1952 to 1955.
Johnson adopted a left-wing political outlook during this period as he witnessed, in May 1952, the police response to a riot in Paris, the "ferocity [of which] I would not have believed had I not seen it with my own eyes." (Communists were rioting over the visit of an anticommunist commander, Matthew Ridgeway, during the Korean War.). Then he served as the New Statesman's Paris correspondent. For a time, he was a convinced Bevanite and an associate of Aneurin Bevan himself. Moving back to London in 1955, Johnson joined the Statesman's staff.
Some of Johnson's writing already showed signs of iconoclasm. His first book, about the Suez War, appeared in 1957. An anonymous commentator in The Spectator wrote that "one of his [Johnson's] remarks about Mr Gaitskell is quite as damaging as anything he has to say about Sir Anthony Eden", but the Labour Party's opposition to the Suez intervention led Johnson to assert "the old militant spirit of the party was back". The following year, he attacked Ian Fleming's James Bond novel Dr No and in 1964 he warned of "The Menace of Beatlism" in an article contemporarily described as being "rather exaggerated" by Henry Fairlie in The Spectator.
He was successively lead writer, deputy editor and editor of the New Statesman magazine from 1965 to 1970. He was found suspect for his attendances at the soirées of Lady Antonia Fraser, then married to a Conservative MP. There was some resistance to his appointment as New Statesman editor, not least from the writer Leonard Woolf, who objected to a Catholic filling the position, and Johnson was placed on six months' probation.
Statesmen And Nations (1971), the anthology of his Statesman articles, contains numerous reviews of biographies of Conservative politicians and an openness to continental Europe; in one article Johnson took a positive view of events of May 1968 in Paris, an article which at the time of first publication led Colin Welch in The Spectator to accuse Johnson of possessing "a taste for violence". According to this book, Johnson filed 54 overseas reports during his Statesman years.
In the 1970s, Johnson became increasingly conservative in his outlook and has largely remained so. In his Enemies of Society (1977), following a series of articles in the British press, he opposed the trade union movement, perceiving it as violent and intolerant, terming trade unionists "fascists". As Britain’s economy faltered, Johnson began to advocate the future British Prime Minister Margaret Thatcher’s message of less government and less taxation. He was eventually won over to the Right and became one of Thatcher's closest advisers: "In the 1970s Britain was on its knees. The Left had no answers. I became disgusted by the over-powerful trade unions which were destroying Britain," he recalled in 2004.
After Thatcher's victory in the general election of 1979 Johnson advised on changes to legislation concerning trade unions and was also one of Thatcher's speechwriters. Johnson was quoted in 2004:
"'I was instantly drawn to her,' he recalls. 'I’d known Margaret at Oxford. She was not a party person. She was an individual who made up her own mind. People would say that she was much influenced by Karl Popper or Frederick Hayek. The result was that Thatcher followed three guiding principles: truthfulness, honesty and never borrowing money.'"
From 1981 to 2009, Johnson wrote a column for The Spectator; initially focusing on media developments, it subsequently acquired the title "And Another Thing". In his journalism, Johnson generally deals with issues and events which he sees as indicative of a general social decline, whether in art, education, religious observance or personal conduct. He has continued to contribute to the magazine, less frequently than before. During the same period he contributed a column to the Daily Mail until 2001. In a Daily Telegraph interview in November 2003, he criticised the Mail for having a pernicious impact: "I came to the conclusion that that kind of journalism is bad for the country, bad for society, bad for the newspaper".
Johnson is a regular contributor to The Daily Telegraph, mainly as a book reviewer, and in the United States to The New York Times, The Wall Street Journal, Commentary and the National Review. He also writes for Forbes magazine. For a time in the early 1980s he wrote for The Sun after Rupert Murdoch urged him to "raise its tone a bit".
Johnson is a critic of modernity because of what he sees as its moral relativism, and finds objectionable those who use Charles Darwin's theory of evolution to justify their atheism or use it to promote biotechnological experimentation. As a result, Richard Dawkins and Steven Pinker have been a target of Johnson's criticism. As a conservative Catholic, Johnson regards liberation theology as a heresy and defends clerical celibacy, but departs from others in seeing many good reasons for ordination of women as priests.
Admired by conservatives in the United States and elsewhere, he is strongly anticommunist. Johnson has defended Richard Nixon in the Watergate scandal, finding his cover-up considerably less heinous than Bill Clinton's perjury and Oliver North's involvement in the Iran-Contra Affair. In his Spectator column, Johnson defended his friend Jonathan Aitken, has expressed admiration for General Augusto Pinochet and (qualified) admiration for General Franco.
Johnson was active in the campaign, led by Norman Lamont, to prevent Pinochet's extradition to Spain after Pinochet's arrest in London. "There have been countless attempts to link him to human rights atrocities, but nobody has provided a single scrap of evidence," Johnson was reported as saying in 1999. In Heroes (2008), Johnson returned to his longstanding claim that criticism of Pinochet's regime on human rights grounds came from "the Soviet Union, whose propaganda machine successfully demonised [Pinochet] among the chattering classes all over the world. It was the last triumph of the KGB before it vanished into history's dustbin".
He has described France as "a republic run by bureaucratic and party elites, whose errors are dealt with by strikes, street riots and blockades" rather than a democracy.
He served on the Royal Commission on the Press (1974–77) and was a member of the Cable Authority (regulator) from 1984 to 1990.
In 2006, Johnson was honoured with the Presidential Medal of Freedom by U.S. President George W. Bush. On the BBC programme Desert Island Discs in January 2012, Johnson professed himself unimpressed by Nelson Mandela.
He was appointed Commander of the Order of the British Empire (CBE) in the 2016 Birthday Honours for services to literature.
Paul Johnson has been married to the psychotherapist and former Labour Party parliamentary candidate Marigold Hunt, daughter of Dr. Thomas Hunt, physician to Winston Churchill, Clement Attlee and Anthony Eden, since 1958. They have three sons and a daughter: the journalist Daniel Johnson, a freelance writer, editor of Standpoint magazine, and previously associate editor of The Daily Telegraph, who is married to the writer and birth educator Sarah Johnson née Thompson; Luke Johnson, businessman and former chairman of Channel 4 Television; Cosmo Johnson; and Sophie Johnson-Clark, who has worked as a television script editor and now resides in the US and is married to Spike Vrusho (aka Mike Clark), the underground sportswriter and author. Paul and Marigold Johnson have ten grandchildren. Marigold Johnson's sister, Sarah, an art historian, married the journalist, former diplomat and politician George Walden; their daughter, novelist Celia Walden, is the wife of television presenter and former newspaper editor Piers Morgan.
In 1998 it was revealed Johnson had an affair lasting eleven years with the writer Gloria Stewart. Stewart went public with the affair to the newspapers after what she saw as Johnson’s hypocrisy over his views on morality, religion and family values.
Johnson is a friend of British playwright Tom Stoppard, who dedicated his 1978 play Night and Day to him.
Johnson is a watercolourist, painting mainly landscapes, who has exhibited regularly.