After spending close to six years with Honda Lock S.C. in the Japan Football League Mizunaga signed for fellow Japan Football League side V-Varen Nagasaki for the 2011 season.
Mizunaga made his full-professional debut in the 2nd Division on 3 March 2013 against Fagiano Okayama in which he came on as a 75th-minute substitute for Kōichi Satō as V–Varen drew the match 1–1.
League Division 2 the very next game against former Japanese champions Gamba Osaka in which was also V–Varen's first home game in the 2nd Division in front of over 18,000 fans in attendance in which he scored in the 79th minute for the club which turned out to be a consolation as V–Varen Nagasaki lost the match 3–1.
League, Mizunaga came back home and joined newly promoted JFL-team Tegevajaro Miyazaki in December 2017.
This biographical article related to a Japanese association football forward, born in the 1980s is a stub.