O. Castellanos is a 27-year-old professional football player from GUA. He currently plays for Antigua GFC, wearing the number 17 shirt. At the international level, he represents Guatemala. He plays primarily as a Defender. His preferred foot is Right.

Throughout the Guatemala Liga Nacional 2025-2026, O. Castellanos featured in 28 matches, averaging 0 tackles, 0 interceptions, and 0 clearances per game, while blocking 0 shots per game.