Gielgud came to be regarded as one of the foremost interpreters of Shakespeare, having portrayed, among other parts, Romeo, Richard II, Macbeth, Prospero, and Antony. He first played Hamlet in 1930, acting the role more than 500 times. Gielgud subsequently established himself as a respected stage director, launching his own distinguished company in 1937 at the Queen's Theatre, performing Shakespeare and other classics such as "School for Scandal", "Three Sisters" and "The Importance of Being Earnest". Throughout his career the theater was a mainstay both in his native London and on Broadway, where he won three Tony Awards, including one for directing the 1961 play "Big Fish, Little Fish". He also directed Richard Burton in "Hamlet" (1964) on the Great White Way, a production that was later filmed.

Gielgud made his screen debut in 1924 in the silent feature "Who Is the Man?" and turned in one of his few romantic film leads in Alfred Hitchcock's "Secret Agent" (1936). His appearance as Cassius in "Julius Caesar" (1953) ended a 12-year absence from features and since then, because of his high forehead, receding hairline and bulbous nose, Gielgud has portrayed primarily supporting characters on the big screen, always managing to stand out and live up to the credo: "There are no small parts, only small actors". He has brought majestic interpretations to any number of cinematic roles, from France's King Louis VII opposite Burton in "Becket" (1964) to the aging career diplomat in the film version of David Hare's "Plenty" (1985). He picked up a Best Supporting Actor Oscar as Dudley Moore's foul-mouthed manservant in "Arthur" (1981) and a New York Film Critics Circle Award as Best Actor for his impassioned dying writer Clive who is attempting to finish his last novel in Alain Resnais' "Providence" (1977). Gielgud returned to the Bard for a daring but unsatisfactory adaptation of "The Tempest", Peter Greenaway's "Prospero's Books" (1991), delivering not only Prospero's speeches but also those of many of the supporting characters, sometimes voicing them simultaneously with other thespians.

Gielgud did not limit himself to the classics on stage but stayed current with the times, acting in plays by Noel Coward, N C Hunter and Graham Greene during the 50s and gracing the angry-young-man projects of such 60s avant garde figures as Edward Albee, Lindsay Anderson and Peter Hall. His starring turn opposite Sir Ralph Richardson on Broadway in David Storey's "Home" (1970) earned him a Drama Desk Award and the pair reteamed to overwhelming success in Harold Pinter's "No Man's Land" (1975-76), with Gielgud again receiving another Drama Desk Award. He retired from the stage after "The Best of Friends" (1988), no longer confidant in his ability to remember his lines, but has continued to work energetically in radio, TV (i.e., PBS' 1992 "Masterpiece Theatre" version of "The Best of Friends"; the 1994 CBS miniseries "Scarlett") and films. For radio, he collaborated with Kenneth Branagh in presenting "Hamlet", "Romeo and Juliet" and "King Lear" and acted in Branagh's Oscar-nominated short "Swan Song" (1992), adapted form a Chekhov play. Gielgud poignantly played an aging actor who takes to the stage of an empty theater and revisits the Shakespearean characters of his career.

Sadly, future generations will have no visual reference for much of Gielgud's greatest work, his prodigious output in the theater, but they can go to both television and films to study his efforts. He made his American TV-movie debut in "Les Miserables" (CBS, 1978), gave a memorable performance as Jeremy Irons' eccentric father in the famous British miniseries "Brideshead Revisited" (PBS, 1982) and garnered a Golden Globe Award as Best Supporting Actor in ABC's miniseries "War and Remembrance" (1988) and an Emmy as Outstanding Lead Actor in a Miniseries or Special for "Summer's Lease" (1991, PBS, Masterpiece Theatre), to cite only a few of his small screen credits. He has remained busy in the films of the 90s, appearing in three high profile movies in 1996 alone, a cameo as Priam Branagh's "Hamlet", as Nicole Kidman's benefactor in Jane Campion's "The Portrait of a Lady" and as David Helfgott's British teacher in Scott Hicks' "Shine". Having outlived many of his contemporaries (e.g., Olivier, Richardson and Dame Peggy Ashcroft) Gielgud has continued to add to his legacy as one of the century's truly great actors.