He graduated from Episcopal Academy in Pennsylvania. At Princeton, where his father had been in the Class of 1922, he was a member of the Liberal Union, the French Club, and treasurer of the German Club. He majored in English.
Stirling lived much of his life outside the U.S. After training in pathology and neurology, he joined the Montreal Neurological Institute at McGill University, where he was the chief of neuropathology from 1977 to 1994. Upon retiring from McGill, he worked for two years as staff neuropathologist at Toronto Western Hospital.
Following his marriage to Ligia Castro, also a neuropathologist, he culminated his longtime love of Portugal, its language and its literature, by moving to her home city of Porto. There he became a consultant at the Hospital de Sao Joao and professor at the University of Porto.
He published more than 200 scientific papers, and with a compatriot wrote Pathology of Skeletal Muscle (1984; 2001), which became the standard reference book on the subject.
Stirling is survived by his wife, Ligia; son, Simao; daughter, Rebecca; and two grandchildren.