The words describe a series of images of hardships that the industrious student endures in his relentless quest for knowledge, starting with the firefly's light, which the student uses to keep studying when he has no other light sources (originating from the story of Che Yin from Volume 83 of the Book of Jin).
It is commonly heard during graduation ceremonies and at the end of the school day.
Many stores and restaurants play it to usher customers out at the end of a business day.
On the very popular Japanese New Year's Eve TV show, NHK's Kōhaku Uta Gassen, it has become a tradition for all the performers to sing Hotaru no Hikari as the last song.
From 1993 until 2020, this was also played at Tokyo Disney Resort during fireworks shows on New Year's Eve.