Miyagi attended Komazawa University, where he won the 39th Prime Minister Cup in July 2010.[1] He was signed by Tochigi Uva in his rookie season.
After leaving because out of contract, Miyagi signed a new deal with JFL newly promoted side Renofa Yamaguchi.[2] He had the opportunity to play as forward, but in the end the club registered him as defender, despite scoring 11 goals in two season.[3] Miyagi was instrumental to win the J3 League in 2015, gaining the first promotion in J2 for Renofa.