In 2005, Morimoto was selected the Japan U-20 national team for 2005 World Youth Championship and he played all 4 matches. In 2008, he also played for Japan U-23 national team at 2008 Summer Olympics. On October 10, 2009, he debuted for the Japan national team against Scotland. He was also selected the Japan for 2010 World Cup, but he did not play in the match. He played 10 games and scored 3 goals for Japan until 2012.