This song is written from the perspective of a dying sheriff:
I can't use it anymore
It's gettin' dark, too dark for me to see
I feel like I'm knockin' on heaven's door
Dylan wrote it for the 1973 Western film, Pat Garrett And Billy The Kid. It plays while Sheriff Colin Baker is dying from his gunshot wounds. Dylan cameos in the movie as the character, Alias.
Booker T. Jones sometimes tells a story of playing bass on this track (he and Dylan were neighbors in Malibu), but Terry Paul is credited as the bass player. Jones is credited on four other songs from the soundtrack.
Guns N' Roses covered this on their 1991 album, Use Your Illusion II. They played it in 1992 at a tribute concert for Freddie Mercury, the lead singer of Queen, who had died of AIDS. 72,000 people attended the concert, which was held in London's Wembley Stadium. In case you're wondering, towards the end of the end of this version, the man on the telephone says, "You just better start sniffin your own rank subjugation Jack, 'cause it's just you and your tattered libido, the bank and the mortician, forever man and it wouldn't be luck if you could get out of life alive."
In 1996, Bob Dylan allowed the Scottish musician Ted Christopher to record a new verse for "Knockin' on Heaven's Door" which Christopher had written in memory of the schoolchildren and teacher killed in the Dunblane massacre. This is one of the rare times Dylan has officially permitted someone to add to or change the lyrics to one of his songs. Christopher's version reached #1 in the UK.
One of the few times Dylan authorized a sample was when he let the British singer Gabrielle use this song as the basis of her 1999 track "Rise," which went to #1 in the UK. According to Gabrielle, Dylan not only allowed it, but waived some of the royalties he was entitled to.
Warren Zevon recorded this for his 2003 album The Wind. Zevon was dying of lung cancer when he recorded the track, and died shortly after the album was released.
This song has been covered in reggae style by multiple artists including G.T. Moore & The Reggae Guitars, Arthur Louis and Eric Clapton.
Other artists to have covered this song include Avril Lavigne, Dolly Parton, Bruce Springsteen, Bon Jovi, Cold Chisel, Neil Young and Aretha Franklin.
The title of the song was used as the original title for the Cowboy Bebop movie. Cowboy Bebop is a popular Japanese Anime that made a big hit in America when the dubbed version (done in the late '90s) was broadcast on Cartoon Network in 2001. Bebop was known for taking influences from pop culture (example: The title of episode 6 is "Sympathy for the Devil," obviously a take off of the Rolling Stones Song). When a full length Bebop movie was made in Japan, it was titled Cowboy Bebop: Knockin' on Heaven's Door. When it was dubbed and brought to theaters in America for a short time, they changed it to Cowboy Bebop: The Movie so Dylan wouldn't take any legal action against them.
This song is musically similar to Neil Young's "Helpless," which was recorded in 1969 and features on the Crosby, Stills, Nash and Young album, Déjà Vu.
In October 2007, 1,730 guitarists in Shillong, India strummed this song for five minutes to set a world record for the largest ever guitar ensemble.