While in opposition, Chan served as Liberal critic for the Federal Economic Development Initiative for Northern Ontario, and critic for the Federal Economic Development Agency for Southern Ontario. In November 2014, he became critic for Tourism and Small Business.
Following the Liberal victory in the October 2015 federal election, Chan became Deputy Leader of the Government in the House of Commons. Chan was known for his advocacy on behalf of the Armenian Canadian community, and chaired the Canada-Armenia Parliamentary Friendship Group. In May 2017, Chan hosted Garo Paylan, an ethnic-Armenian Member of the Turkish Parliament and advocate for minorities in Turkey, when he visited the Parliament of Canada.
Chan had three sons with his wife Jean Yip. Yip won a December 11, 2017 by-election for Chan's former seat.