Donald Dickinson was born in Oswego County, New York, in 1846 and moved with his family to Michigan two years later. A graduate of the University of Michigan Law School in 1867, Dickinson enjoyed a meteoric legal career in Detroit, arguing frequently in front of the United States Supreme Court.

Beginning in 1872, Dickinson became a major figure in Michigan politics as an effective Democratic organizer in the strongly Republican state. An early supporter of the candidacy of Grover Cleveland in 1884, Dickinson earned Cleveland’s private confidence during the campaign. After his election, Cleveland offered Dickinson a seat on the Civil Service Commission, but Dickinson declined the post.

Following the 1887 departure of William Vilas as postmaster general, Cleveland offered Dickinson the post. This time, Dickinson accepted the nomination; he was confirmed in January 1888. Railroad workers went on strike soon after Dickinson took office, interrupting the nation’s mail delivery. Dickinson refused to call in federal forces to break the strike and reworked distribution routes so that mail delivery remained unaffected. Dickinson also applied civil service hiring rules to the post office upon Cleveland’s request, cutting the effect patronage had on his department.

After Cleveland’s defeat in 1888, Dickinson returned to Michigan and the practice of law. As head of the Michigan delegation to the 1892 Democratic National Convention, Dickinson was instrumental in securing the nomination of Grover Cleveland. Nevertheless, Dickinson supported William McKinley and Theodore Roosevelt in 1900, having been alienated by the Democratic Party’s turn toward free silver. He also supported Roosevelt’s independent candidacy in 1912 due to his interest in TR’s program of "New Nationalism."