Captain of Lee's Battery. He joined the Confederate Army at Tullahoma, Tennessee on April 25, 1861. He was killed at the battle of Greenbrier River, Va. Colonel (later General) Edward Johnson, CSA described Captain Anderson's fate: A large column of the enemy "came up on the left of our trenches. They were evidently surprised to find us entrenched. Here the brave Anderson, by a fatal mistake, lost his life. As the enemy advanced he rode to the trenches and inviting them in, thinking they were our returning pickets, at the same time telling our men not to fire. He was instantly shot down by the advanced body of the enemy's force. Our men then opened a galling fire upon them, and they fell back..."

P. B. Anderson was the son of U.S. Senator Joseph and Only Patience (Outlaw) Anderson. He was one of the town founders of Tullahoma and he served in the Tennessee House of Representatives (1843-47)representing McMinn County. He was married to Ann Madison Leeke and they had five children. Before the war he also practised law and taught mathematics at Franklin College in Davidson County.

Upon his death the Richmond Daily Dispatch provided the following obituary:
Capt. Anderson had the appearance of a military man, and everywhere he went would be noticed as a man of mark, and the short time he remained in this place brought to him hosts of admirers. He was one of the most gallant and graceful of men, and was admired and beloved by all under his command.
Captain Anderson was the son of the first Senator sent from Tennessee to the Federal Congress, which place he occupied for eighteen years; afterwards his father was made United States Treasurer, which place he held until his death.
Captain Anderson was sent early to West Point, where he was a contemporary of President Davis and Gen. Lee, and remained there three years, when he received a bayonet wound through his right wrist, which permanently disabled him. He then resigned, and studied law at Winchester under the elder Tucker at the same time with C. J. Faulkner and H. A. Wise. He practiced law in Tennessee, and was frequently elected to the Legislature of that State.
At the breaking out of the Mexican war he raised a large volunteer company, and was in every important engagement from Vera Cruz to Chapultepec, at which latter engagement he acted most heroically, having seventeen of his men killed the first fire, and as an appreciation of his bravery, a sword was presented to him by his company, bearing the following inscription: "Never mind it, boys! Company, forward! Remember, you are Tennesseeans!"
He was the first to raise a company of volunteers in Tennessee for the Southern cause, and was elected as one of the Majors of the 1st Tennessee regiment, but the Confederate States having but one Major for a regiment, he resigned at this place, and then, together with his Lieutenants, raised a splendid corps of artillery of 100 men for during the war, which company has now been in three important battles — the Rich Mountain, Greenbrier, and Alleghany.
Captain Anderson married a granddaughter of Gen. Andrew Lewis, who bore him several children, two sons of which are now in service. He was a resident, at the time he engaged for the war, of Tullahoma, Coffee county, Tenn., and was 56 years old.