[1] Matsunaga was educated at and played for Hamana High School and Aichi Gakuin University.

After he lost his position to young Yoshikatsu Kawaguchi who would also replace him as the first-choice goalkeeper in the national team, he moved to Japan Football League (JFL) side Tosu Futures in 1995.

He came back to J1 League to play for Kyoto Purple Sanga in 1998 and spent 3 seasons there before he retired in 2000.

He was also tending the goal when Japan's hope to play in the 1994 World Cup finals was dashed by a late Iraqi equaliser in the 1994 World Cup qualification final qualifier, the match that the Japanese fans now refer to as the Agony of Doha.

After retiring from the game, Matsunaga served as a goalkeeping coach for Kyoto Purple Sanga from 2001 to 2006.