In 2009, he moved to the newly formed Gangwon FC as a founding member with former Ulsan Hyundai Mipo Dockyard manager Choi Soon-Ho. At the first K-League match against Jeju United, he was injured unexpectedly and will have to go through rehab for eight weeks. On 15 August 2009, he scored his first K-League goal against Chunnam Dragons.
Gwangju FC
In January 2011, Ahn Sung-Nam joined Gwangju FC on loan for 1 year. After a loan spell, he completed his free transfer to Gwangju on 25 December 2011.