Gignac formally takes on the top EDC management job on June 3 when Poloz becomes Canada's top central banker. He is the corporation's chief risk officer.
EDC says Gignac will provide continuity at the federal Crown corporation, which provides financial services to Canadian exporters.
He has been senior vice-president for enterprise risk management since January 2012 after eight years as EDC's senior vice-president for insurance.
Prior to joining EDC in April 1999, Gignac held senior posts during a 14-year career at Metropolitan Life Insurance Co.
The EDC says the search for a permanent president and CEO will be conducted jointly by the board, Privy Council Office and the trade minister.