In August 2007, Seohyun became the youngest member of the South Korean girl group Girls’ Generation. Also known as SNSD, they earned the nickname “The Nation’s Girl Group” in their home country due to their achievements and popularity. In 2017, Girls’ Generation was honored as the top K-pop girl group of the past decade by Billboard. That same year, Seohyun released her first extended play Don’t Say No, which marked her official solo debut.

Seohyun debuted as an actress in the 2013 SBS drama Passionate Love. In 2014, she made her theatrical debut in the musical adaptation of the novel The Moon That Embraces the Sun. In 2016, she played a supporting role in the SBS sageuk Moon Lovers: Scarlet Heart Ryeo, in which she earned a Special Acting Award at the SBS Drama Awards. In 2017, she led the weekend drama Thief-nom, Thief-nim, which won her Best New Actress at the MBC Drama Awards. In 2018, she was nominated for a Top Excellence Award at the MBC Drama Awards for Time.

Seohyun is an only child. She graduated from Dongguk University.