Lieutenant Joel Thiesfeldt enlisted in the U.S. Navy in 2003. Following training, he reported to Navy Band Southwest as a trumpet instrumentalist. Subsequent enlisted duty stations include Navy Band Northwest, Navy Band Great Lakes, and the Naval School of Music, where he graduated from both the unit leader and senior musician courses.

Thiesfeldt received his commission as a naval officer in 2017. After attending the Limited Duty Officer/Chief Warrant Officer Academy in Newport, Rhode Island, he completed tours at U.S. Navy Band in Washington, D.C., U.S. Fleet Forces Band in Norfolk, Virginia, and Navy Band Northwest in Silverdale, Washington. He reported to U.S. Pacific Fleet Band as Fleet Bandmaster in July 2025.

Lt. Thiesfeldt holds a Master of Music degree in conducting from Arizona State University. His military decorations include the Navy and Marine Corps Commendation Medal (three awards), the Navy and Marine Corps Achievement Medal (four awards), and the Meritorious Unit Commendation (two awards).