A natural southpaw, Thomas had his first bout in 2002 and continued his winning ways en route to becoming a two-time Junior Olympic National Champion as well as easily winning the World Championships, garnering praise from Emanuel Steward: "I have a kid who will be the next big thing—Isiah Thomas. I don't have to teach him much, he's a gifted athlete. I haven't seen anyone as good since Mays."[citation needed]
His amateur career, however, stalled somewhat as his two losses against compatriots in 2006 and his loss to Deontay Wilder at the 2007 National Golden Gloves attested.