Born in Chillicothe, Ohio, Douglas attended the public schools of Chillicothe and a preparatory school. He graduated from Kenyon College, Gambier, Ohio, in 1872 and from Harvard Law School in 1874.
He was admitted to the bar in 1874 and commenced practice in Chillicothe, Ohio. He served as prosecuting attorney of Ross County 1877-1881. Presidential elector in 1896 for McKinley/Hobart.
Douglas was elected as a Republican to the Sixtieth and Sixty-first Congresses (March 4, 1907-March 3, 1911).
He was an unsuccessful candidate for reelection in 1910 to the Sixty-second Congress,and resumed the practice of law in Chillicothe, Ohio. He was appointed Ambassador Extraordinary to represent the United States at the centennial of the independence of Peru in 1921.
He retired and resided in Washington, District of Columbia, until his death in that city on March 14, 1935. He was interred in Grandview Cemetery, Chillicothe, Ross County, Ohio, United States of America.
Member 60th and 61st Congresses (1907-1911), 11th Ohio District
Married Lucia C. Taylor, of Brooklyn, April.