Leon competed only in the men's 100 m breaststroke at the 2000 Summer Olympics in Sydney. He received a Universality place from FINA, without meeting an entry time. He participated in heat one against two other swimmers Kieran Chan of Papua New Guinea and Joe Atuhaire of Uganda. Leon pulled away from a small field, and opened up his lead to a top seed in a new Paraguayan record of 1:08.12. Leon failed to advance into the semifinals, as he placed sixty-first overall on the first day of prelims.