Zann was born on November 22, 1959, in Sydney, New South Wales, Australia, the daughter of Janice, a high school teacher, and Paul Zann, a professor. Her great-grandfather, named Zaninovich (Zaninović), came to Australia from Croatia.
She emigrated with her parents to Canada in 1968, first to Regina, Saskatchewan, then to Truro, Nova Scotia, and later graduated from Cobequid Educational Centre, a high school in Truro, which was noted for its student musical productions. She attended York University in Toronto where she studied drama, fine arts and political science.
Zann worked as a screen, television, stage, and voice actress, and appeared in numerous television shows, films, radio, and animated series. As an actor, she is best known for providing the voice of Rogue on the 1992 animated television adaptation of the X-Men comic book series. Zann will be reprising the role in X-Men '97, the series' upcoming Disney+ revival.
After living in Halifax, Toronto, London, Stockholm, Vancouver, Los Angeles, and New York City, Zann returned to Truro in 2008.
That fall she started a community campaign to restore a historic former academic building in downtown Truro, Provincial Normal College, into a cultural centre. She raised $62,000 for a feasibility study following which the four-story, 24,000-square-foot provincially designated Victorian brick building was repurposed to become the centre point of downtown Truro – the town's new Central Colchester Regional Library, with a skating rink in front during winter months.
On April 8, 2009, Zann successfully ran for the Nova Scotia New Democratic Party nomination in the riding of Truro-Bible Hill. Zann was elected in the 2009 provincial election and served as the ministerial assistant for the Department of Tourism, Culture, and Heritage. She was subsequently re-elected in the 2013 provincial election to represent the reconfigured electoral district, now called Truro-Bible Hill-Millbrook-Salmon River.
