He was born in Frankfort, Maine, the son of Henry Treat and the grandson of Colonel Ezra Treat of Maine. He was descended from Robert Treat, who was the royal Governor of Connecticut from 1676-1708. Thereafter, he entered his father"s West Indian shipping business.
He was educated in country schools, and taught in the Academy of Rockport, Maine to pay for his schooling. He graduated from Dartmouth College in 1863.
He developed a great talent for public speaking and organization. He spoke in Maine for James G. Blaine. He was the delegate at large from Delaware to the Republican National convention of 1888 in Chicago.
He was a representative of Delaware in Congress.
In 1896 President William McKinley appointed him the collector of Internal Revenue for the Wall Street District, Elihu Root and Cornelius North. Bliss being his sponsors. He was reappointed by President Theodore Roosevelt in 1902.
In 1905, Treat was appointed Treasurer of the United States by President Roosevelt, a post that he held until July 1909. He was succeeded by Lee McClung.
He died on Monday, May 30, 1910 from apoplexy at the age of 68 in his apartment in the Hotel Victoria around 11:00 a.m.
He was pronounced dead by Doctor Gilday. Funeral services were held June 2, 1910 at 3:00 p.m. at the Grace Church, New York on 802 Broadway near Tenth Street. The services were conducted by Doctor Slattery, rector of the church, who was assisted by the Review
Charles T. Walkley, rector of the Grace Church, Orange, New Jersey, of which Treat was a communicant for fifteen years.
He was a member of the Union League Republicans and West Side Republican Clubs in New New York
