Born in 1974, Imai studied at the Kunitachi College of Music, Tokyo, and IRCAM, Paris. In 2002–2003 he was recipient of a grant from the Japanese Agency for Cultural Affairs, and guest composer at ZKM, Karlsruhe; and the following year served as artist-in-residence at DAAD Berlin, and guest composer at the Electronic Music Studio TU Berlin. From 2008–2011 he directed music of the Bauhaus Stage Projects, Dessau; and in 2012 served as tutor at the Darmstadt Summer Courses for New Music. He is currently associate professor and director of the Sonology Department of Kunitachi College of Music.
His awards include: the Residence Prize at International Electroacoustic Music Competition of Bourges; the First Prize and Special Prize for Young Composer at MUSICA NOVA International Electroacoustic Music Competition in the Czech Republic; Prize at the EARPLAY Composers Competition in USA; and the First Prize at ZKM International Competition for Electroacoustic Music in Germany. His works have been performed at numerous international festivals including Inventionen, Ultraschall, Transmediale, MaerzMusik (solo show at Berghain, Berlin), Darmstadt Summer Courses for New Music, Agora, ICMC, and ISCM World Music Days. In 2004 a portrait concert of his works was held at Berlinische Galerie, Berlin. In 2016 he was composer-in-residence at SinusTon festival in Magdeburg.