*Club domestic league appearances and goals, correct as of 20 July 2020 (UTC) ‡ National team caps and goals, correct as of 16:10, 19 December 2015 (UTC)
Born in Hamburg, Katrín made her club debut for KR of the Úrvalsdeild kvenna when she was 14 years old.[1] She represented KR in the inaugural season of the UEFA Women's Cup in 2001–02.
In January 2013 Katrín signed for Liverpool Ladies, who had finished bottom of the FA WSL in 2011 and 2012 but were investing heavily in improving their team. She scored the second goal as Liverpool beat Bristol Academy 2–0 on the final day to secure the league title.[8] Liverpool retained their league title in 2014 but fared poorly in 2015, finishing seventh of eight teams. Katrín was among four players to be released by the club at the end of the season.[9]
On New Year's Eve 2015 Katrín joined Doncaster Rovers Belles, alongside veteran Liverpool teammate Becky Easton.[10] Doncaster were relegated after only winning one game all season, secured by Katrín's winning goal against Reading F.C. Women. She left the club at the expiry of her one-year contract,[11] and promptly re-joined KR.[12] In November 2020 she joined the coaching staff at KR, but continued to be available a player.[13]
In November 2021, Katrín joined the coach staff of Haukar.[14] She left the club along with manager Guðrún Jóna Kristjánsdóttir in end of June 2022.[15]