In 1961 she married David Harter, a lawyer, and began raising three sons, Joe , Paul and Rick, in Islington, North London where she lives to the present day.
She is a patron of the Palestine Solidarity Campaign.
She wrote Owners, her first stage play, in 1972. Churchill's basic socialist views are very apparent in the play, which is a critique of the values that most capitalists take for granted: being aggressive, getting ahead, doing well. She served as resident dramatist at the Royal Court Theatre from 1974-1975, and later began collaboration with theatre companies such as Joint Stock Theatre Company and Monstrous Regiment (a feminist theatre union) which used an extended workshop period in their development of new plays. Churchill continued to use an improvisational workshop setting in the development of some of her plays.
Her first play to receive wide notice was Cloud Nine (1979), set partly in a British Colony in the Victorian era, which examines the relationships involved in colonisation, and utilizes cross-gender casting for comic and instructive effect.
In time Churchill's writing became less and less inhibited by realism, and the feminist themes were also developed. Top Girls (1982) has an all-female cast, and focuses on Marlene, who has sacrificed a home and family life to achieve success in the world of business. Half the action takes place at a celebratory dinner where Marlene mixes with historical and fictional women who achieved success in a man's world, but always at some cost; the other half in Marlene's family, where the cost is being paid. In The Skriker (1994), Churchill utilises an associative dream logic which some critics found to be nonsensical. The play, a visionary exploration of global ecology made through gender, storytelling, distorted language and modern urban life, follows an ancient and shapeshifting death portent (The Skriker) in her search for love, revenge and human understanding.
Serious Money (1987) is a verse play that takes a satirical look at the stock market, and received enormous acclaim, partly because it played immediately after the stock market crash of 1987. Her 2002 play, A Number, addresses the subject of human cloning. Her adapted screenplay of A Number was shown on BBC TV in September 2008. Her latest play, Drunk Enough To Say I Love You (2006), takes a critical look at what she sees as the submissiveness of Britain to America in foreign policy.
Churchill has written television plays for the BBC, including The After Dinner Joke (1978) and Crimes (1982). These, as well as some of her radio plays, have been adapted for the stage.
She has also published a retranslation of Seneca's Thyestes and her new version of August Strindberg's A Dream Play, premiered at the National Theatre in 2005. Her career is examined in the Reputations strand on TheatreVoice.
The Royal Court Theatre are about to launch a 70th Birthday retrospective of her work by presenting readings of many of her most famous plays directed by notable playwrights including Martin Crimp and Mark Ravenhill.