Born and raised in Tokyo, Japan, Kosuge first studied architecture at the Tokyo Sumida Technical School of Architecture and then went on to receive his MFA in sculpture from the San Francisco Art Institute in 1970. He began teaching art at Portland State University in 1978, becoming a full professor in 1989, and after serving three years as the Chair of the Art Department, retired in 2003. His first exhibition was in San Francisco in 1970, and he has exhibited continuously every since. Exhibitions of his work include the Oakland Art Museum, the Portland Art Museum, the San Francisco Museum of Art, and the Seattle Art Museum. Major commissions include a 5-piece commission for the Portland TriMet Transit Mall, a comprehnsive landscape and sculpture project for Highline Community College, Des Moines, WA; and major works for the River Point Education Center, Spokane, WA; Kaiser Permanente Foundation, Vancouver, WA; the Little Tokyo Mall, Los Angeles, CA; Portland Community College, Sylvania Campus, OR; and the Washington County Justice Center, Hillsboro, OR.