Career
Sellin started playing football at the age of four when he joined his hometown club BKV Norrtälje. After having also spent some time as a youth player at Allsvenskan club Djurgårdens IF he was signed to a first team contract by third tier side IK Brage in 2009. Two and a half year later, in the middle of the 2012 season, he had impressed enough to make the move up to Allsvenskan when he was signed by GIF Sundsvall.
Sellin has represented both the Sweden national under-17 football team and Sweden national under-19 football team on several occasions.
Sellin grew up supporting Djurgårdens IF. Until the age of 15 he combined playing football with Ice hockey before choosing the former as his career.