Entrepreneur, Philanthropist, Horticulturist. He gained recognition as an American munitions manufacturer, becoming the largest American munitions producer during World War I, selling nearly 1.5 billion pounds of explosives to the government and allies. He became very wealthy from this venture. In 1902, he and his cousins, Alfred I. du Pont and Thomas Coleman du Pont, purchased E. I. du Pont de Nemours and Company after the death of company's president, Eugene I. du Pont, and started purchasing smaller powder firms. The company started to produce dyes, paints and plastics besides munitions. He served as treasurer, vice president, and acting-president during T. Coleman du Pont's illness until 1914. The next year, he and a group of outsiders that did not include Alfred bought Coleman's stock. He was then established as President of the DuPont Chemical Company and served until 1919. He was sued by his cousin Alfred for breach of conduct, but the court ruled in his favor though, yet the ruling severed his relationship with his cousin. In 1919, he became Chairman of the Board until his retirement in 1940. After purchasing a majority of stocks in General Motors, he was elected in 1915 as the director, serving until 1920 when he became president until his resignation in 1923. His image was featured on the cover of "Time" magazine in the January 31, 1927 issue. That same year, he was elected an honorary member of the Delaware Society of the Cincinnati. In 1930, he was elected as a director of the Pennsylvania Railroad. He became one of several wealthy investors that formed Empire State, Inc., which built the Empire State Building in New York City. As a philanthropist, he was one of the Delaware Valley's leading, donating over $8 million to build more public schools in Delaware and Pennsylvania. Eighty-six of those schools were for black children due to his disgust at the poor condition of black segregated schools and Delaware State law prohibiting white taxpayer money to fund black schools. He also donated $2 million to the University of Delaware. He contributed over $3 million to local hospitals with $1 million of that to Chester County Hospital. He embarked a public road improvement plan which lasted forty-eight years and cost several million dollars. Of all of his accomplishments and successes, he is most famous for the horticultural creation of Longwood Gardens. In 1906 with the intend of being his personal estate where he could entertain friends and family, he purchased Pierce's Park, a farm and arboretum, renaming the facility Longwood after the nearby Longwood Meetinghouse. In 1907, he designed the first garden and fountain: the Flower Walk, six-hundred-foot-long garden with a simple jet fountain in the middle. The Flower Walk became incredible among guests, leading him to expand his garden. In 1913, he built the open-air theatre, which was inspired by an outdoor theatre near Siena, Italy and his love of music and drama. Within a year, he equipped the theatre with "secret" fountains that shot-out of the stage floor to drench visiting nieces and nephews. In 1927 he redesigned and expanded the theatre to include illuminated fountains set into the stage floor and a 10-foot water curtain at the front. In 1915, as a wedding gift to his bride and first cousin, Alice Belin, he built an extension onto the original Peirce house and connected the new and old wings with a conservatory, planted with exotic foliage and graced with a small marble fountain. The following year, he designed a second conservatory which opened in 1921. This conservatory housed fruits and flowers planted in a decorative way in a giant glass building with hidden tunnels that housed the systems to control the power, heat, and irrigation. In addition, the Conservatory, as it was known, was open to the public. In 1923, a Music Room with a massive, 3,650-pipe Aeolian organ, which had 6,360 more pipes added in 1930, was added to the Conservatory. From 1925 to 1927, he constructed a water garden, inspired by the Villa Gamberaia near Florence, Italy, in a low-lying, marshy site northeast of Longwood's Large Lake. At the same time, he installed a 40-foot-tall jet fountain at the end of the central allée in Peirce's Park. From 1929 to 1930, he constructed Longwood's 61-foot-tall stone Chimes Tower based on a similar structure he had seen in France. In the late 1930s, he built a 30-by-36-foot oval analemmatic sundial in the Topiary Garden. He fully retired in 1940, and the same year, he opened the first healthcare institution established by the Nemours Foundation, a leader in pediatric orthopedics, which is in the 21st century a network of Nemours Children's Hospitals. In 1946, he turned the entirety of his property into the public Longwood Gardens. In 1943, his genealogical research book, "Genealogy of the Du Pont family, 1739–1942", was published. He was the great-great-grandson of the French economist, Pierre Samuel du Pont. "Forbes" magazine reported in 2016 that the DuPont family's fortune is estimated at $14.3 billion.