John Giribaldi Sargent was born in Ludlow, Vermont, on October 12, 1860. He graduated from Tufts University (BA, 1887, MA 1912). He studied law and was admitted to practice in Vermont in 1890. Sargent served as Windsor County state attorney (1891-1900), and as attorney general for Vermont (1900-1902, 1908-1912).

Coolidge appointed him U.S. attorney general on March 17, 1925. He served until the end of Coolidge's term on March 5, 1929. He acted as chairman of the Vermont Commission on Uniform State Laws. Sargent died on March 5, 1939.