Born in Wethersfield, Connecticut, Warner attended Wilbraham Academy, Wilbraham, Massachusetts, and the law department of Yale College.

He graduated from the law department of Harvard University in 1854.

He commenced the practice of law in Portland, Connecticut, in 1855.

He served as delegate to the Republican National Convention in 1864, 1888, and 1892.

[1] This article incorporates public domain material from the Biographical Directory of the United States Congress