Williams went to medical school at the University of Pennsylvania (where he met another budding poet, Ezra Pound), then set up practice in his home town of Rutherford, New Jersey in 1910. Over the next 40 years he delivered babies and poetry with equal aplomb.
How good was he? Well, he delivered 2000 babies and won the Pulitzer Prize.
Lots of medical students have become famous authors, but Williams was pretty rare in keeping up a full-time practice while writing.
Happy 125th, Mr. Williams, wherever you are.