Nayeon was born into a Christian family that consists of her parents and younger sister by three years, Im Seo-yoon.
Nayeon secretly tried out and passed JYP Entertainment's 7th Open Audition and became a trainee on September 15, 2010. In 2013, she was cast as a member of 6mix, a JYP girl group that was planned but never debuted. Prior to Sixteen and her debut as a member of Twice, she appeared in few television advertisements and in several music videos of her label mates, including Jun. K's "No Love", Got7's "Girls Girls Girls" and miss A's "Only You." She also made a cameo appearance in the second episode of KBS2's 2012 Korean drama Dream High 2. In 2017, she, along with Nichkhun, starred in the music video of Jun. K's "Your Wedding".