Brennan believes that youth are the drivers of change. Since Grade 4, he has engaged in fundraising and advocacy, raising over $100,000 to support community projects around the world. In 2013, he founded Pledges for Change, a platform that harnesses the power of youths to take simple actions to change our world, and recognize their potential to effect positive change. In 2014, Brennan was recognized as one of Canada’s Top 20 Under 20. He was selected by Three Dot Dash as one of its 30 2016 Global Teen Leaders, actively working on projects that promote a more peaceful society.