After mustering out of the Union Army on June 20, 1865, Hurlbut was one of the founding fathers of the Grand Army of the Republic, of which he served as commander-in-chief from 1866 to 1868.
He was appointed Minister Resident to Colombia in 1869, where he served three years. In 1872, Hurlbut was elected as Republican from Illinois to the U.S. House of Representatives, reelected in 1874, he was defeated for reelection in 1876. Hurlbut was made ambassador to Peru in 1881, where he served until his death in Lima. He and his spouse are buried together in Belvidere Cemetery, Belvidere, Illinois.