Two years later (now a member of the Michigan State Spartans), Booth moved on to the under-20 level, competing at the 2004 IIHF World Junior Championships, held in Helsinki and Hameenlinna, Finland. He recorded his lone assist of the tournament on Dan Fritsche's game-winning goal in the semifinal against Finland. Booth and the United States went on to win the gold medal with a 4–3 win over Canada in the final. With a goal and an assist over six games, Booth tied for 12th in team point-scoring. In a 2011 interview for Canucks.com, Booth recalled his IIHF U18 and U20 gold medals as his first- and second-best hockey memories, respectively.