Kim Ki-jong was convicted of attempted murder, assaulting a foreign envoy and obstruction, according to Seoul Central District Court spokesman Joon Young Maeng.
Both Kim and the prosecution have one week to determine whether to appeal, Maeng said. Prosecutors had previously asked for a 15-year prison term.
Kim slashed Mark Lippert during a breakfast forum in Seoul, leaving deep gashes on the envoy’s face and arm. Lippert was treated for five days at a Seoul hospital.
Kim has described himself as an anti-U.S. activist. He told police that his assault was meant to protest annual U.S.-South Korean military drills but that he did not intend to kill the ambassador.