She competed in the Women's World Chess Championship 2000, where she reached round 2. Hahn won the 2003 U.S. Women's Chess Championship in Seattle after beating Irina Krush and Jennifer Shahade in a three-way playoff for the title. In the aftermath, there was some controversy when Hahn was not subsequently selected for the Olympiad training squad. This victory qualified her for the Women's World Chess Championship 2004, where she was knocked out in the first round by Pia Cramling.