A member of the Liberal Party, she currently represents the riding of Markham—Stouffville in the House of Commons and formerly served as the Minister of Public Services and Procurement and Receiver General for Canada.
Before entering federal politics in 2019, Jaczek served as a Member of the Legislative Assembly of Ontario from 2007 to 2018 representing Oak Ridges—Markham.
[5] In 2007, Jaczek won the newly formed riding of Oak Ridges—Markham by 7,197 votes beating Conservative candidate Phil Bannon and New Democrat Janice Hagan.
Jaczek was a member of several Standing Committees: Public Accounts, Social Policy, Government Agencies, Finance and Economic Affairs.
In September 2010, she co-sponsored a private member's bill with PC and NDP MPPs to amend the Arthur Wishart Act (Franchise Disclosure) 2000, to better protect prospective franchisees.
"[citation needed] On June 6, 2013, the bill received the support of all three parties, but it died on the order paper because of the 2014 Ontario General Election.
However, in November 2016, the government introduced legislation that included a provision to ensure the direct election of chair and CEO of the Regional Municipality of York.
[citation needed] Jaczek was appointed Chair of Cabinet in addition to her role as Minister of Community and Social Services on January 17, 2018.
The purpose of the funding was improving the quality of and access to community-based services, including the creation of 15 additional youth wellness hubs and more supportive housing.
[9] In the 2018 general election, Jaczek ran for re-election in the new district of Markham—Stouffville which encompassed the eastern portion of her old riding, but was defeated by Progressive Conservative Paul Calandra.
She advocated for funding transparency, greater safety on airlines and better public health standards in the agricultural sector.