Classical roles and revue
Adrian first achieved wide public notice in a nine-month season at the Westminster Theatre from September 1938, as Pandarus in a modern dress Troilus and Cressida and Sir Ralph Bloomfield Bonnington in The Doctor's Dilemma, winning enthusiastic notices from the critics: "Mr Max Adrian triumphantly turns Pandarus into a chattering and repulsive fribble of the glossily squalid night-club type"; "The egregious 'B.B.'... is a great piece of fun, and Mr. Max Adrian rightly draws him with all possible exuberance of line."
Adrian joined the Old Vic company in 1939, playing the Dauphin in Shaw's Saint Joan, "a beautifully malicious study in slyness, effeminacy, meanness, and a curious lost, inverted dignity." He continued classical work with John Gielgud's company at the Haymarket Theatre (1944–45), where he appeared as Puck in A Midsummer Night's Dream, Osric in Hamlet, and Tattle in William Congreve's Love for Love.
Away from the classics, Adrian played the Scarecrow in The Wizard of Oz at the Phoenix Theatre in 1943. In 1947, at the Lyric Theatre, Hammersmith, Adrian began performing in a series of revues (Tuppence Coloured, Oranges and Lemons, Penny Plain, Airs on a Shoestring, From Here to There, and Fresh Airs) in which he played more than 2,000 performances, and established himself, in Sheridan Morley's words, "as a superlative – if eccentric – light comedian." Fellow performers in the revues included Joyce Grenfell, Rose Hill and Elisabeth Welch. Contributors included Michael Flanders, Donald Swann and Alan Melville, and the producer was Laurier Lister, who became Adrian's lifelong partner. Adrian's musical numbers included "Prehistoric Complaint" (as a misfit caveman), "Excelsior" (as a put-upon Sherpa), "Guide to Britten" (as a manic conductor), "In the D'Oyly Cart [sic]" (as a jaded Gilbert and Sullivan performer), and "Surly Girls" (as headmistress of St. Trinian's).
When revue became less popular in the mid-1950s, Adrian went to America in 1956 to appear as Dr. Pangloss and Martin in Leonard Bernstein's operetta Candide on Broadway. The original production was a failure, but the original cast recording has rarely been out of the catalogues in the subsequent half century. He remained in the U.S., working in summer stock in roles as varied as Doolittle in Pygmalion, Jourdain in Le Bourgeois Gentilhomme, Shylock in The Merchant of Venice, and Sir Peter Teazle in The School for Scandal. He returned to London in 1959 to appear in Noël Coward's play Look After Lulu! in which he also later played on Broadway.
In 1960, Adrian joined Peter Hall's newly formed Royal Shakespeare Company (RSC) in Stratford-upon-Avon, together with such actors as Peggy Ashcroft, Peter O'Toole and Diana Rigg. He played Jaques in As You Like It, Feste in Twelfth Night, Pandarus in Troilus and Cressida, the Cardinal in John Webster's The Duchess of Malfi, and Father Barré in The Devils, as well as a range of smaller parts. He also starred with Dorothy Tutin, Richard Johnson and John Barton in The Hollow Crown, an anthology of prose and verse about the monarchs of England, devised by Barton and frequently revived in later years.
Adrian was one of the original members of Laurence Olivier's National Theatre Company at the Old Vic from 1963, and appeared as Polonius in the opening production of Hamlet, in which Peter O'Toole played the Prince. The Guardian called his performance, "sly, dry, and not quite stuffy enough, but every sally from this character was touched with a look of great complicity towards the audience which made something special of this sometimes over-charged part." He then played
the Inquisitor in Saint Joan, Serebryakov in Uncle Vanya, Balance in The Recruiting Officer and Brovik in The Master Builder.