He was born in Newport, Vermont, September 1, 1906; attended The Hill School (Pottstown, PA) and Yale College; mayor of Newport 1938-1941; member, State house of representatives 1941, 1945, 1947, serving as speaker in 1947; chairman of Vermont State Water Conservation Board 1948-1950; officer and director of family-owned lumber and building material enterprises, Prouty & Miller; elected as a Republican to the Eighty-second Congress; reelected to the three succeeding Congresses (January 3, 1951-January 3, 1959); was not a candidate for renomination in 1958; elected to the United States Senate in 1958; reelected in 1964 and 1970 and served from January 3, 1959, until his death; died in Boston, Mass., on September 10, 1971; interment in Pine Grove Cemetery, Newport, Vt.

Prouty died of cancer at 65 while in office in 1971 and was eulogized by President Nixon.

Famously, Prouty's name was invoked by Senator James Jeffords, who said he was following in Vermont's tradition of progressive independent Republicans, like Win Prouty, when he left the Republican party in 2001, which caused the Republicans to lose control of the Senate: "The party I grew up in was the party of George Aiken, Ernest Gibson, Ralph Flanders, Winston Prouty, and Bob Stafford...ach served Vermont as a Republican senator in the 20th century...Aiken and Gibson and Flanders and Prouty and Bob Stafford were all Republicans, but they were Vermonters first. They spoke their minds, often to the dismay of their party leaders, and did their best to guide the party in the direction of those fundamental principles they believed in."

Prouty hailed from one of Vermont's first family. The family owned and operated Prouty & Miller, a lumber and bulding materials company, with extensive land holdings in Canada. His grandfather, George H. Prouty, served as governor of Vermont, 1908-10.