Kerrigan served in Company D, First Regiment, New York Volunteer Infantry, during the Mexican–American War. After the war, he accompanied the Walker filibustering expedition to Nicaragua as a captain and served for a brief period as alcalde of the Nicaraguan capital.
Kerrigan returned to New York City and was elected alderman of the sixth ward. He also served as clerk of the Manhattan Police Court. Upon the outbreak of the American Civil War, he organized and then was commissioned Colonel of the 25th New York Volunteer Infantry Regiment, in the Union Army and served from May 19, 1861, until February 21, 1862. Kerrigan was accused of harboring Confederate sympathies, and of not maintaining good order and discipline among his troops, and was allowed to resign his command.
He was elected as an Independent Democrat to the Thirty-seventh Congress (March 4, 1861 – March 3, 1863). While serving in the House, Kerrigan was arrested and removed from the floor for continuing to speak after his allotted time had expired in opposition to a bill funding the abolition of slavery in Missouri.
After leaving Congress, he became an enthusiastic Irish Nationalist and when the invasion of Canada was planned in 1866 led a company across the border. In 1867, he commanded the vessel Erin's Hope, which landed arms and ammunition on the Irish coast. He also accompanied an expedition to Alaska in 1899 and returned in bad health.
- Thomas P. Lowry, Curmudgeons, Drunkards, and Outright Fools: Courts-Martial of Civil War Union Colonels, pages 94–95
- New York State Division of Military and Naval Affairs, Undressed for Battle: The Short Civil War Career of Col. (Congressman) James Kerrigan, July 3, 2011
- Paul N. Herbert, God Knows All Your Names: Stories in American History, 2010, page 140
- Patrick Steward, Bryan P. McGovern, The Fenians: Irish Rebellion in the North Atlantic World, 1858–1876, 2013, page 130
- Thomas Power Lowry, Tarnished Eagles: The Courts-martial of Fifty Union Colonels and Lieutenant Colonels, 1997, page 97
- San Francisco Call, Colonel Kerrigan has Passed Away, November 2, 1899
- United States Congress. "James Kerrigan (id: K000147)". Biographical Directory of the United States Congress.
- James Kerrigan at Find a Grave
|U.S. House of Representatives|
Thomas J. Barr
| Member of the U.S. House of Representatives
from New York's 4th congressional district