Born in Tokyo in 1960. Studied under designers Choei Hara and Shigemitsu Hara. Established Koizumi Studio in 1990. In 2003, he opened Koizumi Tool Store as a place to communicate his designs. He has designed everything from architecture to chopstick rests, and now travels all over Japan to collaborate with local communities. In 2015, he launched a general incorporated association called Waza, which is dedicated to the restoration of handicrafts. He is a professor emeritus at Musashino Art University. He received the Mainichi Design Award in 2012. In 2015, he won the Grand Prize at the Japan Craft Exhibition.