[1] He was the son of a prominent Bostonian and philanthropist, William Henry Baldwin Sr.[1] He graduated from Harvard University in 1885 and studied law there for a year afterward.

[1] In 1896, the directors of the Long Island Rail Road recruited Baldwin as president, replacing Austin Corbin who had died.

[1] By eliminating around 100 grade crossings, this project made the train ride from Long Island to New York City 30 minutes quicker.

[1] In 1894, he became a trustee of Tuskegee University where he became "the intimate friend of Booker T. Washington, and one of his ablest, wisest and most faithful supporters.

"[2][1] Baldwin's efforts at Tuskegee were considered so important that during the 25th-anniversary ceremonies his name was inscribed onto the lawn in letters several feet long, along with those of Andrew Carnegie and President William Taft.

[4] Described as "a simple type of New England Colonial architecture," the house was fabricated in cement with wood trim and a cypress shingle roof that was stained red.

[4] The Baldwin's home was located on a hill that overlooked Long Island Sound and was near the golf courses of the Nassau Club.

[3] After his death the ferries operated by the Long Island Railroad flew their flags at half mast and the principal stations on the road were draped in black for several days.