Newton Baker was born in Martinsburg, West Virginia, on December 3, 1871. He earned a B.A. from Johns Hopkins University and a law degree from Washington and Lee in 1894, entering into a Martinsburg law firm that year. Baker first arrived in Washington, D.C., as personal secretary to Postmaster General William Lyne Wilson; he remained in that post for two years, starting in 1896. After becoming involved in local politics in Cleveland, Ohio, Baker served as mayor of the city for four years until 1916.

He then took over command of the War Department following the resignation of Lindley Garrison in February 1916. Baker had intended to serve as secretary of war for only one year, but his plans changed when America entered the First World War. He stayed on as war secretary for the remainder of Wilson's first term and served for the entirety of Wilson's second term, leaving office on March 4, 1921.

Baker returned to practicing law in Cleveland before President Calvin Coolidge named him a member of the Permanent Court of Arbitration (the current World Court) at The Hague, Netherlands. He would write Why We Went to War to explain his role in America's entrance into WWI before dying on December 25, 1937.