Great song and there is a story behind it. Headman for the band Dire Straits, Mark Knopfler was in a small pub in southern London and was present for a jazz band playing to the near empty room.
When the show was done the band introduced themselves to their meagre audience as the “ Sultans of Swing” . Apparently to Knopfler their appearance did not quite fit the name the band had chosen for themselves and being that they were playing in a lower end establishment.
The song came into being in 1978 and after some time folk singer Bill Wilson claimed to have co-written the song at some point and was duly compensated. It failed to make the charts after it’s release in 78, but following a re-release in 1979 it began to catch on with fans and gained popularity long since becoming a radio staple.