Folin scored six goals and 14 assists in 41 games during the
2013–14 season with the
UMass Lowell River Hawks. On 1 April 2014, the
Minnesota Wild of the
National Hockey League (NHL) signed Folin as an undrafted free agent to a two-year,
entry-level contract. He made his NHL debut on 10 April 2014, notching an assist for the Wild in a 4–2 win over the
St. Louis Blues. On 1 July 2017, Folin left the Wild as a free agent, opting to sign a one-year, $850,000 contract with the
Los Angeles Kings. In the
2017–18 season, Folin played on the blueline in a third pairing role with the Kings. He notched a season-best of 3 goals and 13 points in 65 games. On 5 July 2018, Folin signed as a free agent to a one-year, $800,000 contract with the
Philadelphia Flyers. Opening the
2018–19 season on the Flyers roster, Folin continued to play in a bottom pairing role appearing in 26 games with Philadelphia, recording two assists, before he was traded with
Dale Weise to the
Montreal Canadiens in exchange for
David Schlemko and
Byron Froese on 10 February 2019. On 18 April, he signed a one-year contract extension with the Canadiens. Folin was waived by the Canadiens on 5 January 2020 and was reassigned to the Laval Rocket. Upon his recall to the Canadiens on 4 February 2020, Folin scored a goal in a 5-4
shootout victory. As a free agent after seven years in the NHL, Folin opted to return to his native Sweden after securing a contract for the remainder of the
2020–21 season with the Växjö Lakers of the SHL on 30 December 2020. ==Career statistics==