Funakoshi was born in Morioka, Iwate Prefecture, as the son of the sculptor Yasutake Funakoshi (1912-2002). He graduated in 1975 from Tokyo Zokei University, and completed his master’s program in sculpture at Tokyo University of the Arts in 1977. Following his first solo exhibition in 1982 at Gallery Okabe (Tokyo), Funakoshi from 1985 onward exhibited mainly at Nishimura Gallery (Tokyo).

A fellowship from the Agency of Cultural Affairs allowed him in 1986-87 to spend one year to study and work in London. He participated in exhibitions outside of Japan, for example the Venice Biennale and Documenta. Funakoshi creates his sculptures mostly of camphorwood, but has also produced woodblock prints and illustrations for novels. Currently, he is teaching at Tokyo Zokei University.