After working as an assistant editor for Warner on Marvel's black-and-white magazine line, Macchio became Dennis O'Neil's assistant editor. Promoted to full editor in 1981, Macchio's first major editing work was "Master of Kung Fu", which he helmed from 1982 to 1983. His first line of books included "The Saga of Crystar" (which he co-created with John Romita, Jr. and Mark Gruenwald), "Dazzler", "ROM", "U.S. 1", and "Micronauts". During this early period, Macchio's assistant editor was Bob Harras, later to become Marvel editor-in-chief.