In August, Mikulak only competed on two events at the 2017 U.S. National Championships in Anaheim, California and maintained his spot on the U.S. national team. His streak of four U.S. national all-around titles was snapped, as he was still recovering from an achilles tendon injury that he suffered in February at the Winter Cup. He won the silver medal on pommel horse and the bronze medal on high bar. In October, he competed only on high bar at the 2017 World Championships in Montreal, Canada, as he was still not fully back from his injury. His quest to capture an individual medal ended when he fell on high bar during the qualification round. As Mikulak was recovering from injury, he continued to host and participate in numerous clinics and workshops for aspiring gymnasts.