How-Sen was born and raised in Etobicoke and has been a climate and climate justice campaigner for nearly 25 years.

Over the years, he's worked with many different environmental organizations, including Sierra Youth Coalition, Sierra Club Canada, Greenpeace, Environmental Defence Canada, Indigenous Climate Action, and the United Nations Development Fund. Between 2016 and 2019, he was the Canadian Digital Campaigner at Stand.earth, where he worked under Indigenous leadership to oppose the Trans Mountain Pipeline.

How-Sen strongly believes that climate progress in Toronto will lead to positive climate action across the country. He holds environmental studies degrees from McGill and Yale and is certified in organizational greenhouse gas accounting. He lives in downtown Toronto.