Barton was educated at Eton College and King's College, Cambridge and while at Cambridge directed and acted in many productions for the Marlowe Society and the ADC. At the Westminster Theatre in July 1953 he directed his first London production, Henry V for the Elizabethan Theatre Company. He created a 12-part series for BBC Radio on the medieval Mysteries, inspired by the York Mystery Plays.
In 1960, along with Peter Hall, he co-founded the Royal Shakespeare Company where Barton was an active director for over 40 years. He has directed over 50 productions on his own or as a collaborator with Sir Peter Hall and Trevor Nunn. Some landmark productions at RSC include 1969's Twelfth Night with Judi Dench as Viola, and the 1963/1964 sequence of Histories (with Peter Hall and Clifford Williams). In the RSC's 50th anniversary commemorations (2011) Barton's teaching is acknowledged as one of the lasting reasons for the company's success and he is regarded as one of the most influential directors of Shakespeare of his time.
At the Aldwych Theatre in London in 1980, Barton directed The Greeks, his adaptations (with playwright Kenneth Cavander) from Homer, Euripides, Aeschylus and Sophocles, ten plays centring on the Oresteia legend, presented in the terse style of the original verse. This was part of an RSC London season which also embraced Trevor Nunn and John Caird's production of David Edgar's eight-hour adaptation of Nicholas Nickleby. "Both projects were daunting undertakings, planned at a time of renewed financial crisis, and both proved remarkably successful."
In 1982, while working with 21 RSC members, including Judi Dench, Ian McKellen, Patrick Stewart, Michael Pennington, David Suchet, Sinéad Cusack, Ben Kingsley, Roger Rees, Jane Lapotaire and Peggy Ashcroft, Barton recorded nine workshop sessions for London Weekend Television. These programs, together entitled Playing Shakespeare, were aired that year and became the source material for Barton's best-selling book of the same name. Though stiff in his resolve against writing on the subject of performing the plays of William Shakespeare, the surprising success of his nine-part televised series convinced Barton of the desire, and of the requisite necessity, for this book. It, too, found great international success, and remains a most popular guide with working actors, (as well as those aspiring to be working actors), who study and train upon the works and words of The Bard of Avon. Playing Shakespeare, the ITV series, is now available on DVD.
Barton is quoted in an article by Michael Billington as saying, "I... think the success or failure of the RSC depends on the quality of the actors. If I've learned anything in my time, it is that if you get the right combination of actors, a production will generally work... But one should always remember that no theatre company is immortal and Zeus could still chuck a thunderbolt at any moment."
Barton possesses an encyclopaedic knowledge of Shakespeare and is known to be able to identify one of his plays from a single line of text. A story is told of Barton getting so into his directorial work giving notes one night, that he fell into the orchestra pit, climbed out, and dusted himself off before resuming. A great deal of the past and continuing success of the RSC is attributed to John Barton and to his unrivalled wisdom of language, verse, character, and voice.
Barton still holds these workshops and even conducts Master Classes at BADA (British American Drama Academy) during their Summer in Oxford training programs. He was awarded the 2001 Sam Wanamaker Prize. Barton believes that the present-day speech of the Appalachian Mountains is the most suitable model for actors who want to imitate the accent used at the time of Shakespeare's plays.
In 1969, he married the former Anne Righter, who eventually became a Professor of English at Trinity College, Cambridge. Anne Barton died in November 2013.
As cast member/instructor:1982 – Playing Shakespeare (TV – Special series)
As writer:1965 – The Wars of the Roses (TV)
1970 – Hallmark Hall of Fame – Hamlet (adaptation) (TV)
1984 – Morte d'Arthur (adaptation) (TV)
1991 – The War That Never Ends (TV)
As director:1965 – War of the Roses (TV)
1968 – All's Well That Ends Well (TV)
As actor:1984 – Morte d'Arthur – Sir Thomas Malory