He picked up a gold medal in Panam taekwondo championships in Oranjsted, Aruba in 2000, and a bronze medal from the 2004 Pan American Championships in Santo Domingo, Dominican Republic.
Sagastume improved his previous Olympic feat by dispatching South Africa's Duncan Mahlangu (11–7) in the prelims and Australia's Carlo Massimino (5–4) in the quarterfinals, before falling in a defeat to Chinese Taipei's Huang Chih-hsiung, who landed him a counterblow by a late surge to produce a 7–5 record.
In the repechage rounds, Sagastume gave himself a chance to campaign for his nation's first Olympic medal, but he was cautiously beaten by Brazil's Diogo Silva with a score of 10–12.Sagastume works for the sports and leisure council in Guatemala, is an international TKD referee, and works on an IOC outreach program that helps athletes to get their lives planified after retirement.