Born in Epping, Plumer attended Phillips Exeter Academy, Exeter, New Hampshire. He graduated from Harvard University, Cambridge, Massachusetts, in 1809, and started his career as a lawyer in private practice and as an author. He was United States commissioner of loans in 1816 and 1817.
Plumer was elected as a Democratic-Republican to the Sixteenth and Seventeenth Congresses and reelected as an Adams-Clay Republican to the Eighteenth Congress (March 4, 1819 – March 3, 1825). He served as chairman of the Committee on the Judiciary (Seventeenth Congress). He was also a close friend and confidant of John Quincy Adams.
He served as delegate to the New Hampshire state constitutional convention in 1850.
Plumer died in Epping, New Hampshire, September 18, 1854. He was interred in the family burial ground on his father's estate near Epping.
- United States Congress. "William Plumer Jr. (id: P000394)". Biographical Directory of the United States Congress.
- William Plumer Jr. at Find a Grave
- William Plumer Jr. at The Political Graveyard
- Magazine article: William Plumer Jr. The Granite State Monthly. March–April 1889. Page 76.
This article incorporates public domain material from the Biographical Directory of the United States Congress website http://bioguide.congress.gov.