It was released by JYP Entertainment on December 11, 2017, as the lead single from Merry & Happy—the group's reissue of their first studio album, Twicetagram.

[3] On November 27, 2017, JYP Entertainment announced the release of the Christmas-inspired reissue of Twice's first full-length album Twicetagram, titled Merry & Happy, on December 11.

[9][10] "Heart Shaker" is composed by David Amber and Sean Alexander, with lyrics by music production team Galactika (별들의전쟁).

[12] Tamar Herman from Billboard described the song as a "bright pop song [that] incorporates funky guitar riffs, twinkling synths, and soft harmonizing to create a vintage wintertime feel, but with an upbeat melody and impish delivery of the verses and the energetic chorus".

[13] The song debuted atop Gaon's Digital Chart and Billboard Korea's Kpop Hot 100.

[16][17] "Heart Shaker" surpassed 100 million streams in September 2019 and 2,500,000 downloads in March 2020 on Gaon Music Chart.

Three days later, the group also attended SBS Love FM's Family Concert, where they performed the song live for the first time.