Poet, Canadian Army Officer. Born in Guelph, Ontario, by the age of 15, he was a first-class military cadet in an artillery regiment that was raised by his father, who was a successful businessman in the bakery business. Achieving early scholarly success, he earned scholarships in medicine. It was during this time that his first love, Alice McCrae (no traceable relation), passed away from a sudden illness. He was so grieved by this that he would never marry. Due to his academic success he was offered a fellowship in pathology, which was offered as the same time as the start of the Boer War, a conflict he chose to fight in (having risen to the rank of Artillery Captain). After the end of that war he took up his fellowship in pathology at McGill University in Montreal. He was also appointed a professor in pathology at the University of Vermont. When World War I began, he enlisted as the Brigade Surgeon and Artillery Officer in the First Brigade of Canadian Field Artillery. As well as performing his duties as surgeon, he also served on the guns when needed. It was after performing a burial service for a friend, Lt. Alexis Helmer (who was killed by an artillery shell direct hit), that McCrae was inspired to write the poem "In Flanders Fields," written on May 3, 1915. The poem became famous shortly after it was published, giving John McCrae a great deal of acclaim for it. But even though he was offered various non-hazardous duties away from the front lines because of his new fame selling war bonds, he insisted on staying with his unit and carried on with his duties. In January 1918, he became ill with pneumonia, which was soon complicated by meningitis. Four days before he died, he was honored by being the first Canadian appointed as consulting physician to the First British Army. John McCrae was then buried with full military honors.

He is honoured by a 'Monument' at the Essex Farm Cemetery at Boezinge, Belgium

and by a 'Cenotaph' inscription at the Woodlawn Cemetery at Guelph, Ontario, Canada.

He was buried at the Wimereux Communal Cemetery at Wimereux, France.