Born in St. Bernard Parish, near New Orleans, Louisiana. Graduate of West Point in 1838 second in a class of 45. Married Laurie Villere in September 1841. Married Caroline Deslonde in 1860.

He served during the Mexican War at Veracruz, Carro Gordo, Contreras and Mexico City. During 1858 to 1861 he was chief engineer on a project to drain the site of New Orleans. He was appointed Superintendent of West Point in February 1861 but resigned in less than a week to become brigadier general in the Confederate Army. He was in command of Charleston, South Carolina and ordered the bombardment of Fort Sumter. He was second in command under Joseph E. Johnston at first Bull Run. He was promoted to full general and joined General Albert S. Johnston in Tennessee. He took command when Johnston was killed at Shiloh. Later he was in charge of the defense of Petersburg against the siege of Grant. He served under Joseph E. Johnston again until the end of the war.

After the war he served as president of the New Orleans, Jackson and Mississippi Railroad for five years. He was Manager of the Louisiana Lottery and Commissioner of Public Works in New Orleans in 1888.

He died in New Orleans.

Beauregard appears on paper money: $20 1863 State of Louisiana, Shreveport bio: ApCAB; DAB; Drake (*gives DOB as 1817); NCAB 4; TCBDA; WAB; WWWA-H (*gives DOB as 1815); NUM 75 Nov 1962 page 1477