The first theatre on Lower George Street, off Sloane Square, was the converted Nonconformist Ranelagh Chapel, opened as a theatre in 1870 under the name The New Chelsea Theatre. Marie Litton became its manager in 1871, hiring Walter Emden to remodel the interior, and it was renamed the Court Theatre.
Several of W. S. Gilbert's early plays were staged here, including Randall's Thumb, Creatures of Impulse (with music by Alberto Randegger), Great Expectations (adapted from the Dickens novel), and On Guard (all in 1871); The Happy Land (1873, with Gilbert Abbott à Beckett; Gilbert's most controversial play); The Wedding March, translated from Un Chapeau de Paille d'Italie by Eugène Marin Labiche (1873); The Blue-Legged Lady, translated from La Dame aux Jambes d'Azur by Labiche and Marc-Michel (1874); and Broken Hearts (1875). By 1878, management of the theatre was shared by John Hare and W. H. Kendal. Further alterations were made in 1882 by Alexander Peebles, after which its capacity was 728 (including stalls and boxes, dress circle and balcony, amphitheatre, and gallery). After that, Arthur Cecil (who had joined the theatre's company in 1881) was co-manager of the theatre with John Clayton. Among other works, they produced a series of Arthur Wing Pinero's farces, including The Rector, The Magistrate (1885), The Schoolmistress (1886), and Dandy Dick (1887), among others. The theatre closed on 22 July 1887 and was demolished.
The present building was built on the east side of Sloane Square, replacing the earlier building, and opened on 24 September 1888 as the New Court Theatre. Designed by Walter Emden and Bertie Crewe, it is constructed of fine red brick, moulded brick, and a stone facade in free Italianate style. Originally the theatre had a capacity of 841 in the stalls, dress circle, amphitheatre, and a gallery. Cecil and Clayton yielded management of the theatre to Mrs. John Wood and Arthur Chudleigh in 1887, although Cecil continued acting in their company (and others) until 1895. The first production in the new building was a play by Sydney Grundy titled Mamma, starring Mrs. John Wood and John Hare, with Arthur Cecil and Eric Lewis. By the end of the century, the theatre was again called the "Royal Court Theatre". Harley Granville-Barker managed the theatre for the first few years of the 20th century, and George Bernard Shaw's plays were produced at the New Court for a period. It ceased to be used as a theatre in 1932, but was used as a cinema from 1935 to 1940, until World War II bomb damage closed it.
After the war, the interior was reconstructed as a stage theatre by Robert Cromie, and the number of seats was reduced to under 500. The theatre re-opened in 1952, with Oscar Lewenstein as the general manager. In 1954, Lewenstein, together with George Devine, Ronald Duncan and Greville Poke, founded the English Stage Company (ESC) with a mission to present plays by young and experimental dramatists and "the best contemporary plays from abroad". Devine served as the first artistic director of the ESC, while Poke was its Honorary Secretary. The ESC purchased the Royal Court in 1956 and began to produce adventurous new and foreign works, together with some classical revivals. The new company's third production in 1956, John Osborne's Look Back in Anger, was a play by one of the Angry Young Men. The director was Tony Richardson. Osborne followed Look Back in Anger with The Entertainer, starring Laurence Olivier as Archie Rice, a play the actor effectively commissioned from the playwright. The artistic board of the ESC initially rejected the play, although they soon reversed that decision. Two members of the board opposed The Entertainer: Duncan disliked Osborne's work, according to the biographer John Heilpern, while Lewenstein, a former Communist, did not want one of the theatre's new plays to be overwhelmed by its star and did not think much of the play. In the mid-1960s, the ESC became involved in issues of censorship. Their premiere productions of Osborne's A Patriot for Me and Saved by Edward Bond (both 1965) necessitated the theatre turning itself into a "private members club" to circumvent the Lord Chamberlain, formally responsible for the licensing of plays until the Theatres Act 1968. The succès de scandale of the two plays helped to bring about the abolition of theatre censorship in the UK. During the period of Devine's directorship, besides Osborne and Bond, the Royal Court premiered works by Arnold Wesker, John Arden, Ann Jellicoe and N.F. Simpson. Subsequent Artistic Directors of the Royal Court premiered work by Christopher Hampton, Athol Fugard, Howard Brenton, Caryl Churchill, Hanif Kureishi, Sarah Daniels, Errol John, David Storey, Timberlake Wertenbaker, Martin Crimp, Sarah Kane, Sylvia Wynter, Mark Ravenhill, Martin McDonagh, Simon Stephens, Leo Butler, Polly Stenham and Nick Payne. Early seasons included new international plays by Bertolt Brecht, Eugène Ionesco, Samuel Beckett, Jean-Paul Sartre, and Marguerite Duras. In addition to the 400-seat proscenium arch Theatre Downstairs, the much smaller studio Theatre Upstairs was opened in 1969, at the time a 63-seat facility. The Rocky Horror Show premiered there in 1973. The theatre was Grade II listed in June 1972.