Born and raised in London, Ejogo is the daughter of Charles and Elizabeth Ejogo née Douglas.During her childhood, Ejogo remembers her mother as being "a bit of a hippie". Her younger brother, also named Charles, was the first successful candidate on the British version of the "business reality" television programme Dragons' Den. In the first episode, broadcast on 5 January 2005, his pitch for investment in an umbrella vending-machine business resulted in Duncan Bannatyne and Peter Jones making a joint offer of 150,000, which he accepted.She attended the Oratory Primary Roman Catholic primary school in Chelsea until 1984.