A Japanese of Korean descent, Ihara joined the Japan Action Enterprise, a theater troupe founded by Sonny Chiba, after leaving high school. Soon after, he began to act in numerous feature films and television dramas, including the 1996 NHK series Futarikko. In 2006, Ihara appeared as the Baron Takeichi Nishi in Clint Eastwood's critically-acclaimed Academy Award-winning film Letters from Iwo Jima, introducing him to an international audience. He has also authored a book, Kokorozashite Sōrō (志して候う, Kokorozashite Sōrō?), which was published in Japan by Amoeba Books.
