Complex sentence: He is the 2013 U.S. national champion, the 2011 U.S. national junior champion, and the 2012 and 2013 U.S. International Classic champion.
Split into simpler sentences: He is the 2013 U.S. national champion. Formerly, he was the 2011 U.S. national junior champion, and the 2012 U.S. International Classic champion.