Mathias Grundetjern is a 25-year-old professional football player from NOR. He currently plays for Vålerenga Fotball Elite, wearing the number 17 shirt. He plays primarily as a Forward. He stands at 182cm tall and weighs 76kg. His preferred foot is Right. His current market value is estimated at 900K €.

His most recent move was a Free from Start Kristiansand to Vålerenga Fotball Elite on 2025-07-16. The reported fee was 0.3M €.

In the Norwegian Eliteserien 2025 season, Mathias Grundetjern scored 4 goals and provided 2 assists across 11 appearances, averaging 0.4 goals per game with 25 shots attempted and 13 on target.