Prior to joining the firm, Derek was an associate at a law firm based in Yakima, Washington where he co-founded and co-led its American Indian Law practice group and assisted clients with litigation and business disputes involving taxation, trade, contract, and issues of Federal Indian law. Previously, Derek worked as a staff attorney for the Yakama Nation Office of Legal Counsel where he represented the Yakama Nation in administrative, state, and federal trial and appellate courts on issues involving treaty rights, water rights, economic development, and tribal sovereignty. He is also a former federal law clerk to the Honorable Brian M. Morris in the U.S. District Court for the District of Montana.

While attending law school, Derek was the Editor-in-Chief of the American Indian Law Journal (2017-2018) and Co-Vice President of the Native American Law Student Association (2015-2017). He also served as a law clerk for the Nez Perce Tribe, Earthjustice, and the Civil Rights Unit at the Washington State Attorney General’s Office.

Derek was recognized as one of the "Best Lawyers: Ones to Watch" in 2023 and 2024 for Native American Law and again in 2025 for both Commercial Litigation and Native American Law by The Best Lawyers in America®. He received the National 40 Under 40 Award from the National Center for American Indian Economic Development (NCAIED). This award recognizes 40 emerging American Indians from across Indian Country who have demonstrated leadership, initiative, and dedication, and made significant contributions in business and/or in their community. Other 2024 NCAIED class members include groundbreaking Indigenous trailblazers like Golden Globe-winning actress Lily Gladstone. Derek also received Yakima’s “39 under 39” award for his leadership and impact throughout his community. Notably, in 2022, he was named a “Successful Indigenous Role Model” for Nez Perce Tribe's Lapwai School District. Derek was also named to the "Top 20 Restorative People Leaders Watchlist" in 2024 by Intersectional Innovations.