Tapu was born and raised in Hauula, Hawaii and is a proud graduate of Kahuku High School and later went on to receive his degree from Dartmouth College, majoring in Native American Studies and minoring in Public Policy and Education. Following college, Tapu worked for almost 10 years in the non-profit sector. His work primarily entailed supporting Pasifika youth and their families.
Tapu then earned his law degree from the University of Hawaii William S. Richardson School of Law. He published extensively on topics ranging from LGBTQ rights, constitutional law, and Indigenous rights. His work has appeared in publications such as the Arizona Law Review, NYU Review of Law & Social Change, and the UCLA Asian Pacific American Law Journal. He was also honored by the National LGBT Bar Association with the Student Leadership Award.