After retirement, Imanishi became a manager for Mazda as Teruo Nimura successor in 1984. This season was the first season the club was relegated to Division 2. He promoted the club to Division 1 in 1986. In 1987, he resigned a manager and Hans Ooft became a new manager. However, the club was relegated to Division 2 again in 1988. Imanishi became a manager as successor Ooft again in 1988. Imanishi promoted the club to Division 1 in 1991 and he resigned in 1992. From 1994, he worked for Japan Football Association until 2002. He also served as president at FC Gifu from 2008 to 2012.