[1] Early on in his career, he recorded songs for the soundtracks of various television shows, such as "So Goodbye" (2011), which sold over 400,000 downloads.

The EP topped the South Korean Gaon Album Chart and spawned the number-one single "Déjà-Boo".

Jonghyun released a collaboration single with Heritage titled "Your Voice" on March 18, 2016, for the project SM Station.

Its lead single, "Lonely", gained success following Jonghyun's suicide in December 2017, rising to number one on the Gaon Digital Chart.

[5] It became Jonghyun's first album to rank on the Billboard 200, making him the fourth Korean soloist to appear on the chart.