Pierre Samuel "P.S." du Pont (1870-1954) was an industrialist, entrepreneur, and philanthropist. He was president of E.I. du Pont de Nemours & Company from 1915 to 1919 and chairman of the board of directors from 1919 to 1940. P.S. du Pont was the great-grandson of Eleuthère Irénée du Pont (1771-1834), founder of E.I. du Pont de Nemours & Company, and the great-great-grandson and namesake of the French economist Pierre Samuel du Pont de Nemours (1739-1817).

Born in 1870, P.S. du Pont was the third child and eldest son of Mary Belin (1839-1913) and Lammot du Pont (1831-1884). P.S. du Pont had ten siblings: four brothers and six sisters, two of whom died at a young age. The patriarch of the family, Lammot du Pont, was a chemist and the inventor of B blasting powder, using Chilean sodium nitrate instead of the previously used potassium nitrate (saltpeter) from India. In 1879, Lammot du Pont resigned from the DuPont Company and formed the Repauno Chemical Company to manufacture high explosives. The family moved from the Brandywine to Philadelphia and lived at 3500 Powelton Avenue. Lammot du Pont died in an explosion on March 29, 1884. In 1892, Mary Belin du Pont had a family home built called Saint Amour in Wilmington, Delaware.

P.S du Pont graduated from the Massachusetts Institute of Technology in 1890 and became assistant superintendent of the Du Pont Company's black powder mills in Delaware. In 1901, he hired John J. Raskob (1879-1950) as his personal secretary. Du Pont had met Raskob while managing and later overseeing the liquidation of the Johnson Company in Lorain, Ohio.

In 1902, he worked with two cousins, T. Coleman du Pont (1863-1930) and Alfred I. du Pont (1864-1935), to reorganize the Du Pont Company. With T. Coleman as president, P.S. became vice president, treasurer, and assistant secretary. As a member of the Finance Committee, he played a pivotal role in reorganizing the company into a large, modern corporation. In 1915, P.S. du Pont purchased T. Coleman du Pont's stock and became president of the company. He was also elected director of the General Motors Company, which at the time was near bankruptcy. Working with Alfred Sloan (1875-1966), he reorganized the company and, in 1920, replaced William C. Durant (1861-1947) as president.

Early in 1906, a lumber mill intended to cut down several hundred acres of trees in Kennett Square, Pennsylvania. This prompted P.S. du Pont to purchase 200 acres of former farmland with the intention of saving the trees. The farm had belonged to five generations of the Peirce family before falling into disrepair and non-familial ownership. In 1914, P.S du Pont completed the Peirce-du Pont house or Longwood Mansion. In 1919, construction began on the main conservatory. Over time, Du Pont drew on his interest in horticulture and developed several different types of gardens, greenhouses, fountains, a ballroom, music room, an organ, and a theater. Du Pont and his wife, Alice Belin du Pont (1872-1944), hosted many garden parties, family affairs, and events for several organizations. Prior to his death in 1954, P.S du Pont established a foundation for the arboretum and botanical gardens: Longwood Gardens. Longwood Gardens is open to the public and attracts more than 1 million visitors per year.

Along with an active business career, P.S. du Pont was involved in social issues and philanthropic concerns. During the 1920s, he was a pivotal member of the Association Against the Prohibition Amendment. In the years between 1934 and 1941, he was a member of the American Liberty League. Du Pont was also concerned with issues in his native state of Delaware; these included improving African American education and building better roads, especially on Kennett Pike.

P.S. du Pont died without children in 1954.