 Morimoto has represented Japan at the Japan U-20 national team level at both the 2004 AFC Youth Championship and the 2005 World Youth Championship.In 2008, he was a member of the Japan U-23 national team for the 2008 Summer Olympics, where the team was eliminated in the preliminary round, losing all three matches and only managing to score one goal.On 10 October 2009, Morimoto made his debut for the senior national team against Scotland, coming on as a substitute for Ryoichi Maeda in a 2–0 win.