Spencer Morton Clark was born in Vermont and was involved in a variety of business activities until 1856 when he became a clerk in the Bureau of Construction of the Treasury Department in Washington, D.C.

On August 29, 1862, Clark commenced work with one male assistant and four female operatives, according to a 1977 Washington Post article.

[1] In another version, Clark ordered that the portrait of Francis E. Spinner, treasurer of the United States, be placed on the 50-cent note without consulting him.

According to numismatic historian Walter Breen, Congress’s "immediate infuriated response was to pass a law retiring the 5¢ denomination, and another to forbid portrayal of any living person on federal coins or currency."

Clark resigned from the National Currency Bureau in 1868 amidst a congressional investigation into record-keeping and security within the agency.