Deanna Mousseau is from the Kul Wicasa Oyate and Oglala Sioux Tribe. She earned a Bachelor of Science in Business Administration with a focus on Human Resource Management from Black Hills State University.

Her dedication to social justice began in high school when she attended the Encampment for Citizenship, a leadership program focused on social justice and community organizing. She spent two summers in the program and later returned as an intern, deepening her understanding of social movements. She continues to support the nonprofit today.

Committed to serving Indigenous communities, Deanna completed the Native Youth Grantmakers program with Native Americans in Philanthropy. She also serves on the Foster Care Youth & Alumni Policy Council, where she advocates for policy changes that support foster youth and Native communities impacted by the foster care system.

In her free time, Deanna enjoys expressing her creativity through writing, scrapbooking, and puzzles. Her favorite pastime is helping on her family's ranch and cherishing time with loved ones.