Chan won the Liberal nomination for
Scarborough—Agincourt after incumbent Liberal MP
Jim Karygiannis resigned to run for
Toronto City Council. He was elected to Parliament with 59 per cent of the vote in a by-election held in 2014. 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. On January 22, 2015, Chan revealed to the public that he would take a five-week leave of absence while undergoing treatment for
nasopharyngeal cancer. Upon his return, he resumed his role and criticized the Harper government's partisan use of public advertising, and their lack of promotion of Canada in the global tourism market. 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. saying "I am not sure how many more times I will have the strength to get up and do a 20-minute speech in this place, but the point I want to impart to all of us is that I know we are all honourable members, I know members revere this place, and I would beg us to not only act as honourable members but to treat this institution honourably," adding "I would ask all of us to elevate our debate, to elevate our practice." ==Personal life==