MacCurdy was Canadian by birth, and a co-founder of the American Psychoanalytic Association. He came to Cambridge in 1923, where he worked as a lecturer in psychopathology, a lectureship created for him by Rivers (Rivers had also referred one of his own most famous patients, Siegfried Sassoon, to MacCurdy). MacCurdy was a Fellow of Corpus Christi College, where he convened informal evening discussion groups for students which were formative for the next generation of psychologists and intellectuals. A correspondent of Sigmund Freud, MacCurdy was interested in dreams; he also later explored the psychology of economics. The MacCurdy Psychopathology Library in the Department of Psychology, still bearing his name, is part of his legacy.