Ahn Gil-kang made his film debut in 1997 through the action comedy flick Trio and has since become a regular in both the big and small screens. In 2008, he was cast in the SBS sageuk drama Iljimae, which earned him a Best Supporting Actor nomination at the SBS Drama Awards. In 2009, he became part of the megahit MBC sageuk Queen Seon-deok, in which he received a Golden Acting Award at the MBC Drama Awards. In 2017, he took home another Golden Acting Award at the MBC Drama Awards for the weekend series Thief-nom, Thief-nim. In 2019, he joined the cast of the SBS sageuk drama Nokdu Flower, which was headlined by Jo Jung-seok, Yoon Shi-yoon, and Han Ye-ri. The following year, he bagged the Best Supporting Actor trophy at the KBS Drama Awards for his performance in the political romantic comedy Memorials.

Ahn Gil-kang has been married since 2006. He and his wife have two daughters together.