It was composed by Do As Infinity's Nagao Dai, who had previously worked for artists such as Ayumi Hamasaki.

On February 14, it was announced that Seven would donate all the proceeds earned from the single to help undernourished children in South Korea.

[4] Following the release of the song, he signed another endorsement contract with Lotte Confectionary, worth ₩400 million.

[6] In South Korea, it was the 7th best-selling non-Korean record during the first half of 2005, selling over 21,570 copies according to the MIAK charts.

[7] Seven held an autograph session commemorating the release of "Hikari" at Gwanghwamun in Seoul on February 23, with more than 2,000 people in attendance.