[1] He served in most of the leading battles of the Army of Northern Virginia and led a brigade of infantry in the Shenandoah Valley in the last years of the war.

His father, James M. Lilley (1802–1875), a prominent landowner and patented inventor of surveying instruments, was commissioned in 1838 as a colonel in the Virginia militia.

Lilley studied at Washington College before beginning a career selling surveying instruments invented by his father.

[3] He was temporarily promoted to brigadier general on May 31, 1864 and given command of Pegram's old brigade of Virginia Regiments in Ramseur's Division of the Second Corps.

[2] Robert D. Lilley died of paralysis in Richmond, Virginia on November 12, 1886, and is buried in Thornrose Cemetery in Staunton.