He initially worked as a watchmaker, until he moved to Freedom, Maryland and engaged in agricultural pursuits.
During the War of 1812, Little was commissioned colonel of the Thirty-eighth Maryland Infantry and served from May 19, 1813, to June 15, 1815.
In 1817, Peter and his wife Catharine had a son named Lewis Henry Little who went on to be a Brigadier General in the American Civil War.
After the War, Little was elected as a Democratic-Republican to the Fourteenth Congress to fill the vacancy caused by the resignation of William Pinkney.
This article incorporates public domain material from the Biographical Directory of the United States Congress