He studied the classics and Arabic in preparation for a career in the Egyptian Civil Service.
[2][3] Johnson returned to Oxford during World War I, physically unfit for military service.
He became Assistant Secretary to the Delegates of Oxford University Press.
In 1918, he married Dorothea, the daughter of his supervisor Charles Cannan.
During that time, he became a collector of what he called "printed ephemera", establishing "The Constance Meade Memorial Collection of Ephemeral Printing" at Oxford University Press.