Matsunaga was born in Shizuoka Prefecture on August 8, 1948. After graduating from Waseda University, he joined Japan Soccer League club Hitachi in 1971. In 1972, the club won the champions in Japan Soccer League and Emperor's Cup. The club also won 1975 Emperor's Cup and 1976 JSL Cup. He scored many goals in early 1970s and competed with Kunishige Kamamoto for top scorer. Matsunaga retired in 1982. He played 176 games and scored 82 goals in the league and became a top scorer in 1972 and 1973. He was also selected Best Eleven for 4 years in a row (1972-1975).