Foster was born in
Barnet, Vermont, a son of Jacob Prentiss Foster and Matilda (Cahoon) Foster. He attended the public schools in Barnet and graduated from
St. Johnsbury Academy in 1876 and
Dartmouth College in
Hanover, New Hampshire, in 1880. He studied law and was
admitted to the bar in 1883. He began the practice of law in
Burlington, Vermont. Foster served as
Chittenden County State's Attorney from 1886 until 1890. He served as a member of the Vermont State Senate from 1892 until 1894. Foster was the first president of the Young Men's Republican Club of Vermont, which was organized in 1894. He was state tax commissioner from 1894 until 1898. He served as chairman of the board of railroad commissioners from 1898 until 1900, and as chairman of the commission representing the United States at the first Centennial of the Independence of Mexico at Mexico City in 1910. Foster was the chairman of the United States delegation to the general assembly of the International Institute of Agriculture at Rome in May 1911. Foster was elected as a
Republican candidate to the
Fifty-seventh and to the five succeeding Congresses, serving from March 4, 1901, until his death in Washington, D.C., on March 21, 1912. He served as chairman of the Committee on Expenditures in the Department of Commerce and Labor during the
Fifty-ninth,
Sixtieth and
Sixty-first Congresses. He served as the chairman on the Committee on Foreign Affairs in the Sixty-first Congress. Foster was interred in
Lakeview Cemetery in Burlington, Vermont. ==Personal life==