His father, who was of Scots-Irish extraction, was a paper maker, and carried on business in New York City.

Some members of the Croswell family were connected with notable events in New York and Connecticut, including Harry Croswell, a pro-Federalist newspaper editor, convicted of libel against President Thomas Jefferson in a landmark case in New York.

According to one biography, he "worked at it very diligently ... maintaining himself, and devoting his spare time to reading and the acquirement of knowledge.

In 1854, he took part in the formation of the Republican Party, where he was a member and Secretary of the convention held at Jackson, Michigan.

In 1855 he formed a law partnership with Thomas M. Cooley, who later became Chief Justice of the Michigan Supreme Court.

In 1868, he was chosen an elector on the Republican presidential ticket, casting, with his associates, the vote of the State of Michigan for Grant and Colfax.

[4] In 1876 he was nominated by the Republican Party, for Governor of Michigan, and was elected by a majority of 23,434 over his Democratic competitor.

During his administration the public debt was greatly reduced; a policy adopted requiring the state institutions to keep within the limit of appropriations; laws enacted to provide more effectually for the punishment of corruption and bribery in elections; the State House of Correction at Ionia and the Eastern Asylum for the Insane at Pontiac were opened, and the new capitol building at Lansing was completed and occupied.

During his second term, he presided at the dedication of the capitol building and helped prevent great destruction of a riot in Jackson.

Lucy Croswell died of spinal apoplexy on March 19, 1868, while her husband was at the state Republican convention in Detroit.

[7] One afternoon in December 1886, he sat down by the stove in the offices of the Lenawee County Savings Bank and complained of a chill.