Throughout her life, Kidder was also invested in efforts protesting for environmental and anti-nuclear causes. On August 23, 2011, Kidder, Tantoo Cardinal, and dozens of others were arrested while protesting in Washington, D.C. against the proposed extension of the Keystone Pipeline. In 2012, she appeared in a video for "Stop the Frack Attack", an environmental organization working toward regulating hydraulic fracturing ("fracking") practices. When discussing sustainable energy, Kidder said: "The first thing people have to start facing, contrary to the advertising fed to us by oil and gas companies, is that environmentalism and economic stability go hand-in-hand on any long term basis." Kidder spent the winter of 2016–2017 residing in a tent at the Standing Rock Reservation in North Dakota, protesting the Dakota Access Pipeline.