Started out as translator and editor. Editor for Central Park Media 1997-2000. Associate editor for Marvel from 2002-2006. Under the Yoshida pseudonym, he wrote various titles for Marvel, Dark Horse, and other companies. Reportedly to bypass Marvel's rule that an editor could not write for his own titles. In 2006 he briefly left Marvel to go freelance as both a writer and editor. He returned to Marvel exclusively in 2007. Creator of Runaways spin-off The Loners from Marvel. As of November 2017 he became Marvel's editor-in-chief.