The track was originally issued in May 1962 on the Volt label (a subsidiary of Stax Records) as the B-side of "Behave Yourself" on Volt 102; it was quickly reissued in August 1962 as the A-side of Stax 127, and it also appeared on the album Green Onions that same year.Green Onions didn't have a "side" initially or a "name" when it first aired according to Steve Cropper.
It was an instant success and people called in for it.
There was a label change to get the 45 to market, based on the instant success.
Yes, there was another side to it, but green onions carried the day, according to Steve.
According to wiki