He was born in Rouen. After customary schooling, Georges Guillain commenced the study of medicine in his native town, but after two years moved to Paris, where he received his clinical education at several hospitals. He soon became interested in neurology, and his first scientific work, of 1898, concerns lesions of the plexus brachialis. He received his medical doctorate at Paris in 1902.
He became chef de clinique for nervous disease and was agrégé in 1910. After the war he served at the Charité Hospital until his career was crowned with the professorship of neurology at the famous Salpêtrière Hospital in Paris in 1923. He held this position until his retirement in 1947.
Guillain was a busy writer. In 1920, with his friend Jean Barré, he published a large work on clinical experiences during the war.
He died in Paris.