Abbott was born in Lennoxville, Quebec. He attended Bishop's University, graduating with a B.A. He then attended McGill Law School, but interrupted his studies to sign up for service overseas, in 1916. Returning from the Great War, he completed his legal studies, earning his B.C.L. He then went to France to attend the Université de Dijon. Returning to Canada, he was called to the Barreau du Québec in 1921 and practised law in Montreal.
As of 2014, Abbott was the last Justice of the Supreme Court of Canada appointed directly to the Court from the Cabinet of Canada, and the last Justice to have held elected office prior to his appointment.