Featuring lyrics written by vocalist Eddie Vedder and music co-written by Vedder and guitarists Mike McCready and Stone Gossard, "Light Years" was released on July 10, 2000, as the second and final single from the band's sixth studio album, Binaural (2000).

We changed the tempos, and then one night Mike and I, after working on it all day and getting frustrated, just flipped it backwards, and in about 35 minutes it became "Light Years", with words and everything.

[3]At the Pinkpop Festival in 2000, Vedder dedicated "Light Years" to Diane Muus from Sony Music, a friend of the band who died at the age of 33 in 1997.

In Allmusic's review of the "Light Years" single, it was stated that "with [Pearl Jam's] more enduring and darker tones set in place, fans of Pearl Jam receive a raw and sincere taste of the band's new musical and melodic direction, perhaps ignited with the additional presence of newcomer Matt Cameron on drums.

"[6] NME called the song "painfully beautiful"[7] in its review of Binaural, while Keith Cameron of NME said in his review of the song, "The specifics of what "Light Years" is about—the death of a friend, apparently—get subsumed into the song's plangent distillation of regret, thereby rendering it perversely uplifting, a trick only the most accomplished and sincere bands can execute with anything approaching conviction.

"[9] "Light Years" was first performed live at the band's May 10, 2000, concert in Bellingham, Washington at the Mount Baker Theatre.

At the band's Chicago concert on August 20, 2016, Pearl Jam dedicated this song to The Tragically Hip, whose lead singer Gord Downie had publicized his diagnosis with glioblastoma earlier in the year and who were playing the final date of their Man Machine Poem Tour that same night.