He currently plays for Grotta Seltjarnarnes, wearing the number 30 shirt. He plays primarily as a Midfield. His preferred foot is Right. His current market value is estimated at 150K €.

His most recent move was a from Valur Reykjavík Youth to Grotta Seltjarnarnes on 2026-04-05.

Across 2 appearances in the UEFA European U17 Football Championship 2025-2026, Mattías Kjeld registered 0 goals and 2 assists, while completing 0 key passes out of 0 total passes with a passing accuracy of -.