After his career at Ridley, Sabia attended the University of Toronto for his undergraduate studies and earned his graduate degree from Yale University. He held a number of senior positions in Canada's federal public service during the 1980s and early 1990s, including Deputy Secretary to the Cabinet of the Privy Council Office. His supervisor, Clerk of the Privy Council Paul Tellier, left the public service to assume the presidency of Crown corporation Canadian National Railway in the early 1990s and subsequently persuaded Sabia to follow him to help in privatizing the company. He held a number of executive positions at Canadian National Railway during the 1990s, including the position of chief financial officer. Sabia left Canadian National to join Bell Canada Enterprises in 1999, and became chief executive in 2002. In 2007, his board accepted an offer from the Ontario Teachers' Pension Plan to privatize the telecommunications company. Later that year, Sabia said he would leave Bell after the privatization deal was finalized. He left Bell in July 2008, but by December 2008, following the collapse of the debt market, the privatization deal fell apart. Sabia was named chief executive of the Caisse de dépôt et placement du Québec on March 13, 2009.