He was married to Gladys Dallas Hamilton, and had one daughter, Sita Hamilton. Earl and Gladys did extensive research on the economic history of Spain.
He was professor of Duke University from 1927 to 1944; Northwestern University from 1944 to 1947, and University of Chicago from 1947 to 1967. The State University of New York appointed him Distinguished Professor of Economic History (1966-1969). Editor of Journal of Political Economy for seven years. President of Economic History Association (1951-1952).
His major contribution was the history of prices in Spain: the concept of Price Revolution in the 16th century. The work of Hamilton was coincident intellectually with keynesianism and contemporary crisis of 1929. He started his work on this topic within the International scientific committee on price history, within which he was responsible for Spain.
He died on 7 May 1989.