Ahn Jae-hyun debuted as a fashion model in 2009. He then made his acting debut in the widely popular SBS fantasy rom-com You From Another Star in 2013. His work in the series won him rookie acting trophies at the Korea Drama Awards and the SBS Drama Awards. He was also nominated for Best New Actor at the 3rd APAN Star Awards for the 2014 SBS series You’re All Surrounded. In 2015, he landed his first leading role in the KBS2 fantasy medical drama Blood. In 2016, he joined the main cast of the tvN romantic comedy Cinderella and the Four Knights, which gave him several awards, including Best Actor at the 7th Macau International Television Festival. That same year, he starred in his first Chinese film Perfect Imperfection, opposite Chinese actress Ady An. In 2017, he scored an Excellence Award nomination at the SBS Drama Awards for the fantasy romance series Reunited Worlds. In 2018, he became part of JTBC’s Beauty Inside. In 2019, he was paired with Oh Yeon-seo in the MBC rom-com People With Flaws, which earned him a Top Excellence Award nomination at the MBC Drama Awards.

Ahn Jae-hyun completed his mandatory military service early in his modeling career. In March 2016, the agencies of Ahn Jae-hyun and his Blood leading lady Gu Hye-sun confirmed their relationship. They married in May 2016. In 2020, the couple became legally divorced after going through a messy public spat.