"Green Onions" is one of the great instrumentals of the 60s. Rock instrumental hits are few and far between because rock instrumentals are dependent upon four variables in order to become popular. To be a hit, a song must satisfy all four criteria: (1) Melody (2) Mood (3) Novelty (4) Title.

(1) Rock 'n' roll is generally a very simple musical format. Rock 'n' roll
succeeds because it is emotionally compelling, not because of instrumental flash or complexity. (At least this was true until the rise of art rock - Yes, E.L.P., Genesis, Rush in the 70s.) Therefore, melody is of paramount importance. An instrumental melody must be so compelling that it atones for the missing vocals. When people want to hear rock 'n' roll, they want to hear vocals. If they want instrumentals, they'll listen to jazz or easy listening or take a ride in an elevator - hence the relative scarcity of instrumental hits.

(2) Once a compelling melody is created, it has to be put into an appropriate setting - this is the arrangement. The arrangement determines which instruments play which parts, how fast or slow, how it's all mixed together, etc.

In the early-'60s, Booker T. Jones (organ), Steve Cropper (guitar), Al Jackson Jr. (drums), and, first Lewis Steinberg, then Donald "Duck" Dunn (bass) became Booker T. and the MG's, (an acronym for "Memphis Group"). Not only did the band write and produce numerous hits for itself ("Green Onions" "Hang 'Em High" "Time Is Tight") based upon Jones' cool organ and the subtly cooking rhythm section, it also played on records and on stage with Stax giants Otis Redding, Sam & Dave, Eddie Floyd and Albert King. They were arguably the greatest backup band of the rock era.

The mood of "Green Onions" is cool, green and funky, a kind of pungent catwalk. In place of emotion or story as conveyed by lyrics, the successful instrumental must convey a mood, an aural story. "Green Onions" does this well.

(3) Because of its lack of lyrical emotion or story line, the instrumental must draw attention to itself, even beyond a good melody and an interesting setting. It must be different. The surf sound was different when it came to the fore, but its novely soon wore out. "Green Onions" was novel because it distilled the newly emerging soul sound but took off the top end of vocal histrionics associated with the genre. The song was a door into soul for white people who couldn't yet handle the intensity of the singing style.