A Southern Unionist, he commanded the Union Army's First Tennessee Infantry during the Civil War, and saw action at Cumberland Gap, Stones River, and in the Knoxville and Atlanta campaigns.

Jesse Byrd, Robert's grandfather, established a ferry at Kingston in the 1790s, when Fort Southwest Point was still in operation.

In 1853, he was appointed to a seven-man commission tasked with fundraising and surveying a route for the proposed South Carolina, Tennessee and Kentucky Railroad.

While in Greeneville, Byrd made a secret pact with several other convention delegates, including Joseph A. Cooper and Richard M. Edwards, to return to their respective homes and begin raising and drilling military units to provide for the region's defense.

[9] Byrd fled to Kentucky in August 1861, and was mustered into the Union Army as a colonel on September 1 of that year, in command of the First Tennessee Volunteer Infantry.

[8] During the first half of 1862, the First Tennessee was involved in numerous skirmishes in the Cumberland Gap area, and was present at the Battle of Mill Springs.

Toward the end of the battle, Byrd led an attack that drove a force of Confederate soldiers out of a patch of woods near the front lines, and was singled out for distinction by the brigade commander, General James G. Spears.

During operations in the aftermath of the battle on January 5, 1863, Byrd led a "fearless charge" that drove three Confederate regiments from their position along a road outside of Murfreesboro.

In June of that year, the unit joined a raid led by Colonel William P. Sanders that destroyed railroad lines and bridges in the areas around Knoxville.

[14] By 1867, Byrd had come to support the "Conservative" faction in state politics, which sought leniency toward former Confederates, and opposed civil rights for freed slaves.

[21] In 1878, Byrd ran unopposed for the Tennessee Senate seat representing the fifth district, which consisted of Roane, Cumberland, Campbell, Morgan, Scott, Fentress, Overton, White and Putnam counties.

[25] In an 1879 interview, Byrd explained that he supported paying the state's debt in full because he didn't want future generations to pass his grave and say, "there lies a damned old repudiationist.

[29][30] Byrd was appointed to the Board of Directors for the Knoxville, Cincinnati and Southern Railroad in 1880,[31] and announced plans to build a narrow gauge line from Kingston to Emory Gap (along the Cumberland Plateau) in 1882.