After the war, Beauregard received a presidential pardon and regained his U.S. citizenship. He faced the challenge of rebuilding his life in a drastically changed South.

Beauregard worked as a railroad executive, including serving as president of the New Orleans, Jackson and Great Northern Railroad. He sought to contribute to the economic recovery of the South.

Beauregard served as a supervisor of the Louisiana Lottery, an endeavor that was controversial due to accusations of corruption. He believed it was a way to generate revenue for the state.

In his later years, Beauregard became a public speaker and author, writing about his experiences in the Civil War and defending his actions. He sought to shape the historical narrative of the conflict.

P.G.T. Beauregard died in New Orleans on February 20, 1893, at the age of 74. He was buried in Metairie Cemetery, a place where many other notable Confederate figures are interred.