Born in Toronto, Ontario, Casey Baldwin was educated at Ridley College and the University of Toronto, graduating from the latter in 1906 with a degree in electrical and mechanical engineering. Like his later aviation associate Doug McCurdy, he was a member of The Kappa Alpha Society. The following year he moved to Baddeck in Cape Breton, Nova Scotia to work with inventor Alexander Graham Bell. With an interest in aviation, the two men teamed up Douglas McCurdy, Glenn Curtiss and Thomas Selfridge to form the Aerial Experiment Association.
Baldwin used his engineering skills to help build the Silver Dart plus several other experimental aircraft and on March 12, 1908 he became the first Canadian, and either the third or fourth North American, to pilot an airplane. William Whitney Christmas claimed to have first flown his aircraft on various dates from September 1907 to March 1908 near Fairfax, Virginia. The first two successful pilots were, of course, the famous Wright brothers, but it seems unlikely that it will ever be firmly established whether Christmas or Baldwin was the so-called "Third Man."
In the summer of 1908 Casey Baldwin and Alexander Graham Bell began discussing powered watercraft and began building and testing various types before turning to the construction of an aircraft that could take off from water that the two called a "hydrodrome." While the project was temporarily shelved, in 1919 Baldwin built the HD-4 hydrofoil that set a world water speed record of 70.86 mph on Bras d'Or Lake. However, the watercraft was not a commercial success and the HD-4 project was ended in 1921.
Following the death of Alexander Graham Bell (August 2, 1922), Casey Baldwin continued boat building and experimenting in hydrofoils in Cape Breton as Director of Graham Bell Laboratories. Bell's last words in 1922 were "Stand by Casey," an encouragement to his family to continue Baldwin's work. A local celebrity, in 1933 Baldwin was elected to the Provincial Legislature as the member from Victoria County.
Casey Baldwin died in Beinn Bhreagh, Nova Scotia in 1948. Following its creation, in 1974 he was inducted posthumously into Canada's Aviation Hall of Fame. In his honour, the "Casey Baldwin Award" is granted annually by the Canadian Aeronautics and Space Institute to the authors of the best paper published in the Canadian Aeronautics and Space Journal.