In 1975, when Ishii played for Fujita Industries, he became a playing manager as Yukio Shimomura successor. The club won the champions in 1977 and 1979. The club also won 1979 Emperor's Cup. He left the club in 1980. In 1986, he named a manager for the Japan national team as Takaji Mori successor. He managed at 1986 Asian Games. However, at 1988 Summer Olympics qualification in October 1987, following Japan's failure to qualify for 1988 Summer Olympics, he resined a manager. In 1988, he returned to Fujita Industries and managed the club. However, in 1989–90 season, the club was relegated to Division 2 and he resigned as manager.