 Oliver Spaulding again served as a special agent of the United States Treasury in 1885, 1889, and 1890 and then as Assistant U.S. Secretary of the Treasury from 1890 to 1893 during the Benjamin Harrison administration and 1897 to 1903 during the McKinley administration.He was also president of the first International American Customs Congress, held in New York City in January 1903 and again a special agent of the United States Treasury from 1903 to 1909 and then customs agent from 1909 to 1916.He married Mary Cecilia Swegles on August 12, 1862.