[4][1][5] Zarrillo's work as a councillor focused on a diverse set of issues, including campaigns to promote anti-vaping and anti-cigarette butt causes, as well as gender equity.

[6] On greenlighting the City Centre Area Plan (CCAP), Zarrillo expressed concerns about the displacement of low-income housing.

[7] Zarrillo was criticized following her decision to leave a city council meeting without prior notice to attend a National Day of Action Against Anti-Asian Racism rally at Lincoln station.

[11] Zarrillo was nominated as the New Democratic Party's candidate in Port Moody—Coquitlam to succeed outgoing MP Fin Donnelly, who had held the seat for a decade.

[12] Zarrillo announced her campaign for the seat on International Women's Day, and five weeks after winning a third term on the Coquitlam City Council.

"[16][17] In addition to outgoing MP Fin Donnelly, Coquitlam-Maillardville MLA Selina Robinson, Kwikwetlem First Nation Chief Ed Hall, the New Westminster and District Labour Council, and Unifor Local 2000 endorsed Zarrillo.

[19][5][12] Fin Donnelly, now serving as MLA for Coquitlam-Burke Mountain in the Legislative Assembly of British Columbia, Amy Lubik of Port Moody City Council, Chris Wilson of the Coquitlam City Council, and Chief Ed Hall of the Kwikwetlem First Nation endorsed Zarrillo.

[11] Zarrillo won in her rematch against Shin, with 62.2 percent of voter turnout in the riding, flipping the seat back to the New Democratic Party.

[25] Zarrillo opposes the Trans Mountain pipeline expansion project, stating the need for urgent climate action.

At the age of 48, Zarrillo quit her position as a business analyst after she was diagnosed with breast cancer in order to focus on her treatment and recovery.