Louis Douglas Watkins was born in the state of Florida, about 1835,[1] but in early life took up his residence in the District of Columbia, where he was living at the time of the outbreak of the Civil War.

[2] He was commissioned captain on July 17, 1862, was on mustering and disbursing duty at Cincinnati, Ohio, and aide-de-camp on the staff of General A. J. Smith during the invasion of Kentucky by the Confederates.

He was then appointed chief of cavalry in the Army of Kentucky and engaged in General Carter's raid to East Tennessee in December, 1862.

[2] He commanded the 3rd Brigade, 1st Division, Army of the Cumberland, until September, 1863, and was engaged in guarding the railroad in the Atlanta Campaign, defeating the Confederates in the Battle of LaFayette, Georgia.

[5] Meanwhile he had been commissioned lieutenant-colonel of the 20th United States Infantry in July, 1866, and was stationed at the posts of Baton Rouge and New Orleans, Louisiana.