In 2013, Seohyun's acting career began when she was cast in a small role in SBS's drama Passionate Love. She played Han Yu-rim, a veterinary student and first love of the male lead character. Director Bae Tae-sub said Seohyun's persona "perfectly paralleled that of her role" and "her understanding and expressiveness of the character exceeds those of a rookie actress".
In 2013, as an effort to help less-fortunate students with their studies, she donated 100 million Korean won to Dongguk University. She went on to major in theatre acting and graduated from Dongguk University in August 2014, receiving an achievement award at the graduation ceremony. Her fellow Girls' Generation member, Yoona, attended the same university.