Imanishi was born in Hiroshima on January 12, 1941. After graduating from Tokyo University of Education, he joined his local club Toyo Industries (later "Mazda") in 1963. In 1965, Toyo Industries joined new league Japan Soccer League. The club won the champions for 4 years in a row (1965-1968). The club also won 1965, 1967 and 1969 Emperor's Cup. He retired in 1969. He played 42 games in the league. He was selected Best Eleven in 1966.