See biography by J. B. Bishop (1923).
After work as a lawyer he served in the New York State Assembly from 1875-1880, becoming chairman of the Legislative Committee to Investigate Railroad State Discrimination. The final report of this committee, commonly called the Hepburn Report, influenced future legislation which helped with the adoption of the federal Interstate Commerce Act in 1887.
Hepburn later was appointed as superintendent of the New York State Banking Department by Governor Alonzo B. Cornell. He then served as National Bank Examiner for the cities of New York and Brooklyn before his appointment as Comptroller of the Currency by President Benjamin Harrison.
After leaving the office of Comptroller he worked in the field of banking, becoming the president of the Third National Bank of New York then the Vice-President of the National City Bank in 1897 when the Third National Bank merged with other banks to form that company. He then became the President of the Chase National Bank.
In 1906 he was given an honorary degree by St. Lawrence University.
Somewhat of a philanthropist, Hepburn donated funds to allow for the construction of a library for each school he served as a District Superintendent.
A prolific writer on the economy and financial matters, he wrote the books "History of Coinage and Currency in the United States: Perennial Contest for Sound Money" (1903), "A History of Currency in the United States" (1915), and "Artificial Waterways and Commercial Development". He also regularly contributed to magazines and periodicals.