Hailing from Sula, Määttä joined Langevåg at the onset of his teenage years, then regional greats Aalesund in 2018 at the age of 17. The next year he made his league debut for Aalesund and won his first Norway youth caps.[1]
Born in Norway, Määttä is of Finnish descent on his father's side.[3] He is a youth international for Norway, having represented the Norway U18s and U20s.[1]