Tanner received his B.A. in International Relations from the University of California, Davis in 2012. After graduating from college, he commissioned through the U.S. Army Officer Candidate School, and served as an Armor Officer from 2013-2017, completing overseas tours to Korea and Kuwait. After leaving active duty, Tanner continued his service as a Civil Affairs Officer with the U.S. Army Reserve, specializing in the Korean peninsula. He is currently a J.D. candidate at Columbia Law School.