I was asked this recently, and the longest one I could think of was “American Pie,” clocking in at a little over eight minutes.
I’m mainly interested in US releases, but other countries are OK. To qualify, it had to have been released as a single, and received significant airplay. So, Rare Earth’s “Get Ready,” about 20 minutes long, wouldn’t qualify, since the single release was much shorter. “Stairway to Heaven” doesn’t qualify, since it didn’t chart (or at least not Billboard’s Top 10).
On the American charts, Isaac Hayes’ cover of “By the Time I Get to Phoenix”–18 minutes and 42 seconds long–made the Top 40 in 1969. However, the shorter single version was played more often on the radio.
Heatwave’s Always And Forever charted at #18. There is a single cut that’s three and a half minutes long, but that was not the one that played on the radio when I was young. It was the one that was over six minutes long that we heard in NYC.
I betcha there are some of us of a certain age that can sing every improvised note, quaver and warble of that six minute and fourteen second song.
In Australia in the late 70s a single was release by Stevie Wright from the Easybeats including the founding writers and driving force behind a little known band called AC/DC Anyway the single was Evie Pt1,2 and 3. The song was sort of like an opus, but the radio stations played it as the full version even though you could legitimately separate the three parts out into seperate songs. But it worked better as one long song and spent a lot of time at No1 on the charts here despite running 11 minutes and 10 seconds. It also charted well in Europe, although I am not 100% sure whether they might have just run Pti of the song. But it is an epic and the writing team and performers went on to create the power house that is AC/DC.