It was released as a digital single on November 27, 2012, and distributed through CJ E&M Music.

"Passing By" was the winning song of Mnet's talent competition series Superstar K4.

Four days after winning Superstar K4, Kim's digital single "Passing By" was released.

[4] As of February 2013, "Passing By" has sold nearly 654,000 digital copies in Kim's native country.

Aside from a performance on Superstar K4,[6] Kim also performed the song at the 14th Mnet Asian Music Awards on November 30, 2012, followed by Mnet's M Countdown on December 13 that same year.