On the original hit single version, the track begins with Lewis singing "I couldn't sleep at all last night," and it appears this way on most oldies compilations. However, on some releases the song has a prelude, where Lewis sings "Baby...Baby...you did something to me," followed by a musical cue into the first verse. Lewis usually includes this prelude when he performs the song live. The personnel on the original hit recording included Ritchie Adams and Eric Gale on guitar, Bob Bushnell on bass, King Curtis on a tenor sax mouthpiece, Frank Haywood Henry on baritone sax, Paul Griffin on Piano, and Sticks Evans on drums.
In 2008, Billboard magazine ranked the song as the 27th biggest song of all time that charted on the Billboard Hot 100, commemorating the 50th anniversary of the chart. It is one of only six songs from the 1960s to spend at least seven weeks in the number one position on the Billboard Hot 100.