The Honourable John Babbitt McNair was born to James McNair and Francis Anne Lewis on November 20, 1889, in Andover, Victoria County, New Brunswick. As a youth he attended Andover Grammar School and Florenceville Consolidated School before enrolling at the University of New Brunswick in 1907. He distinguished himself as a scholar before graduating with his B.A. in 1911, receiving numerous awards including the Lieutenant-Governors Award and served as his class valedictorian. He was awarded a Rhodes Scholarship to attend Oxford University, where he further distinguished himself by earning first-class honours, and received a B.A. in 1913 and a B.C.L. in 1914.