Ahn Jae-hong began his acting career in the 1996 movie Crocodile when he was 10 years old. In 2012, he and his co-stars Shim Hee-sub and Kim Chang-hwan took home the Director’s Guild of Korea Award at the 17th Busan International Film Festival for the movie The Sunshine Boys. In 2013, he headlined the indie sports comedy movie The King of Jokgu, which won him Best Actor at the 2nd Wildflower Film Awards and Best New Actor at the 15th Director’s Cut Awards. In 2016, he was cast in the hit tvN series Answer Me 1988, which recorded a peak audience rating of 18.8 percent for its finale episode. His performance in the drama earned him a Best New Actor nomination at the 52nd Baeksang Arts Awards.  In 2017, he became part of the KBS2 series Fight My Way, in which he won the Best New Actor trophy at the 31st KBS Drama Awards. He also scored a Best Supporting Actor for TV nomination at the 54th Baeksang Arts Awards for his work in the series.

In 2016, Ahn Jae-hong confirmed that he was dating a non-celebrity who attended the same university as him. However, the couple parted ways in 2019 as revealed by the actor’s agency.