Strachey was born in Nutley, New Jersey, USA, the daughter of Henry Smyth Florence, an American musician, and Mary Sargant Florence, a British painter. Her elder brother, Philip Sargant Florence, later became a noted economist and married the pioneer birth control activist Lella Faye Secor. Alix was educated in England at Bedales School, the Slade School of Fine Art, and Newnham College, Cambridge, where she read modern languages. In 1915 she moved in with her brother in his flat in Bloomsbury and became a member of the Bloomsbury Group, where she met James Strachey, then the assistant editor of The Spectator. They moved in together in 1919 and married in 1920. Soon afterwards they moved to Vienna, where James, an admirer of Freud, began a psychoanalysis with him.
Freud asked the couple to translate some of his works into English, and this was to become their lives' work. Both became psychoanalysts themselves, and as well as Freud's works also translated works by a number of other European psychoanalysts. Their translations remain the standard editions of Freud's works to this day.
- Bloomsbury and Psychoanalysis