Born in London to Nigerian parents, Iyiola initially trained to be a barrister and read Law at Emmanuel College, Cambridge University.
Iyiola began her career at the RSC, playing in: A Midsummer Night's Dream, The White Devil, Arden of Faversham, The Roaring Girl, A Life of Galileo, Boris Godunov, The Orphan of Zhao.
[8][9] In 2018, Iyiola returned to the RSC to work with Director Maria Åberg, starring as The Duchess of Malfi in the Royal Shakespeare Company's 2018 summer season.
"[10] Dominic Cavendish, chief theatre critic at the Telegraph commented, "Superb as the Duchess, Joan Iyiola is first fierce, proud and stylish".
[11] In The Times, Maxie Szalwinska highlighted, "Iyiola's raw-voiced final lament summons wider agonies of racial and feminist struggle.