Gustavo Jose Armendariz, Jr received his Doctor of Medicine from University of Southern California. He received a Bachelor of Science in Liberal Arts (Premed) from Arizona State University. After completing an Orthopedic Residency program at USC and a Foot and Ankle Fellowship at The Wagner Institute in Whittier, California, he joined The Orthopedic Clinic Association (TOCA) in Phoenix, Arizona where he practiced until his retirement in 2022.

He served on the Orthopedic Committee and Trauma service at both Saint Joseph's Medical Center and Good Samaritan Hospital, now Banner University Medical Center. He also served as chief of staff at Tempe Saint Luke's Hospital. He was a Fellow of the American Academy of Orthopedic Surgeons and a member of the American Orthopedic Foot and Ankle Society. He currently holds emeritus status with those organizations. He had the pleasure of serving as a team doctor for the Phoenix Suns, Phoenix Mercury, Arizona State University and Grand Canyon University and their sports medicine programs.

Gus is an active member of Valley Presbyterian Church in Paradise Valley. He has served as a deacon, Eldar and Stephen minister there. He has volunteered at Mentor Kids Paiute campus since its inception.