Congressman, and his uncle Edward Stanly served as military governor of eastern North Carolina during the Civil War.

[8] His influential father managed to obtain for his son a second lieutenant's commission in the 6th U.S. Infantry on July 10, 1839, at roughly the time his classmates graduated.

[2] Armistead continued in the Army after the Mexican War, assigned in 1849 to recruiting duty in Kentucky, where he was diagnosed with a severe case of erysipelas, but he later recovered.

Armistead was posted to Fort Dodge, but in the winter he had to take his wife Cecelia to Mobile, Alabama, where she died December 12, 1850, from an unknown cause.

However, a Mohave attack on civilians on the Beale Wagon Road diverted his regiment to the southern deserts along the Colorado River to participate in the Mojave Expedition of 1858–59.

Lt. Col. William Hoffman, at the head of a column of six companies of infantry, two of dragoons, and some artillery, struggled up the Colorado River from Fort Yuma.

On April 23, 1859, Colonel Hoffman dictated a peace to the overawed Mohave chiefs, threatening annihilation to the tribe if they did not cease hostilities, make no opposition to the establishment of posts and roads through their country, and allow travel free from their harassment.

Trouble broke out with the Mohave a few weeks later when they stole stock from a mail station that had been established two miles south of Fort Mojave, and attacked it.

Accounts say that in a farewell party before leaving to join the Confederate army, Armistead told Hancock, "Goodbye; you can never know what this has cost me.

"[13] When the war started, Armistead departed from California to Texas with the Los Angeles Mounted Rifles, then traveled east and received a commission as a major, but was quickly promoted to colonel of the 57th Virginia Infantry regiment.

He fought as a brigade commander at Seven Pines, and then under General Robert E. Lee in the Seven Days Battles (where he was chosen to spearhead the bloody assault on Malvern Hill), and Second Bull Run.

At Antietam, he served as Lee's provost marshal, a frustrating job due to the high levels of desertion that plagued the army in that campaign.

Armistead led his brigade from the front, waving his hat from the tip of his saber, and reached the stone wall at The Angle, which served as the charge's objective.

Dr. Daniel Brinton, the chief surgeon at the Union hospital there, had expected Armistead to survive because he characterized the two bullet wounds as not of a "serious character."

[citation needed] In Gettysburg, the film version of Michael Shaara's novel The Killer Angels, Armistead was portrayed by actor Richard Jordan, who died shortly afterwards.