John Gillespie Magee was born in Shanghai, China, to an American father and a British mother, who both worked as Anglican missionaries. His father, John Magee Sr., was from a family of some wealth and influence in Pittsburgh, Pennsylvania. Magee Senior chose to become an Episcopal priest and was sent as a missionary to China. Whilst there he met his future wife, Faith Emmeline Backhouse, who came from Helmingham in Suffolk and was a member of the Church Missionary Society. Magee's parents married in 1921, and their first child, John Junior, was born 9 June 1922, the eldest of four brothers.