Lien was born on 30 September 2001 in
Flekkefjord, Norway. He studied economics. As a youth player, Lien joined the youth academy of Norwegian side Flekkefjord FK. He started his senior career with the club. He made nineteen league appearances and scored twelve goals while playing for them. In 2018, he signed for Norwegian side
Start. He was described as "impressed for the Start juniors" while playing for the club. He made one league appearance and scored zero goals while playing for them. In 2020, he was sent on loan to Norwegian side
Flekkerøy. In 2021, he signed for the club. He made forty-eight league appearances and scored fourteen goals while playing for the club. In 2022, he signed for Norwegian side
Mjøndalen. By mid-July, he was the top scorer of the
2023 Norwegian First Division with ten goals. In 2023, he signed for Dutch side
Groningen. In 2024, he was sent on loan to Norwegian side
Kristiansund. ==Career statistics==