On May 7, 2005, at the Oregon Twilight Meet, Rupp broke Rudy Chapa's U.S. junior (age 19 and under) record for 10,000 m with a time of 28:25.52, which is still the current North American and Pan American junior record. Two months later, he placed second in the 10,000 m at the NCAA Men's Outdoor Track and Field Championship. On July 17, 2005, Rupp broke Gerry Lindgren's U.S. junior record in the 3000 m in Lignano, Italy, with a time of 7:49.16, also the current North American and Pan American junior record.