[10] Ng has worked for over 20 years in the public service, focusing on the areas of education, women's leadership, job-creation, and entrepreneurship.

[11] Following the resignation of Markham—Thornhill MP John McCallum in February 2017, Ng announced her candidacy for the nomination of the Liberal Party of Canada for the riding.

[12] Ng won the nomination against two other candidates and went on to win the seat with 51.5% of the vote in a riding by-election held on April 3 that year.

As the Member of Parliament for Markham-Thornhill, Ng helped to facilitate the government's commitment to invest in Canadian ideas and innovators in the riding by advocating for the inclusion of Markham's tech-innovation hub, VentureLabs, in the Southern Ontario Supercluster.

[27][28] In 2020, Ng led Canada’s first-ever virtual trade mission to South Korea - an innovative approach to support Canadian businesses during the challenges of the COVID-19 pandemic.

[34][35] When pressed on whether she would resign over this, Ng said "I've said that in making this mistake I need to work very, very hard to earn the trust of those to whom I serve in my riding, but indeed across Canada.

The mission enabled Canadian businesses to establish connections and pursue commercial opportunities in Japan, one of Canada’s top trading partners.

This mission facilitated significant engagements, including the conclusion of negotiations for the Canada-Indonesia Comprehensive Economic Partnership Agreement (CEPA) and the signing of multiple memorandums of understanding between Canadian and Indonesian companies.