The truth is, it all starts with “Billie Jean”.
What do I mean by that? Michael Jackson already had an assured place in history before “Billie Jean”. He certainly accomplished more than enough after that to make him unique in Western media. It was a number one hit, sure, but those were a dime a dozen for him in the 1980s. But I think “Billie Jean” is the single thing that made Michael Jackson meteoric. And, more importantly, it's still the greatest starting point in appreciating Michael Jackson.
It takes little more than a second to see what is so special about this song. Michael Jackson invented his most iconic dance move, the Moonwalk, to evoke the sense of weightlessness so inherent in this song. John Travolta defined himself by 'strutting' down the street to the Bee Gees' “Staying Alive”, and indeed that song's riff is so lighter-than-air that it involuntarily causes anyone listening to it to walk with more of a spring in their step. But it's nothing compared to the bounce of that drum beat. Songs don't live and die by their rhythms, but the propulsive quality of “Billie Jean” immediately singles it out as 'different'. Michael Jackson's best 'fast songs' have always been built around their rhythms, and here it's so clearly the case that (a) every other instrument is, James Brown-style, in service of that rhythm or else mere decoration on top and (b) Michael Jackson's full arsenal of vocal percussion effects are woven into this song so tightly that they are part of the rhythm themselves (a trick that, across his career, is one of the most significant musical innovations Michael Jackson can take credit for). The bed of the song in its entirety is that beat, tied down with an elastic bassline, and that four-note keyboard riff over and over and over again. In service of Michael Jackson's vocals, that bed could go on for only one minute or for twenty minutes and not get tiresome.
After that, it's all in the performance. Given Michael Jackson's later complications regarding public perception of his sexuality, it's interesting to note that this song is (a) an entirely convincing tale of the repercussions of a one-night-stand with a groupie and (b) very sexy in and of itself. Watching the live Motown 25 performance of this, it surprising to recall just how sexy Michael Jackson once was. The reason he became such a superstar (an event traditionally dated to that performance) is in no small part due to the libidinal thrill he gave young girls. Girls who perhaps didn't really care that the song is a denial of paternity (for a boy whose 'eyes were like mine', no less).
After all, it's less what he says than how he says it: driven, purposeful. Michael Jackson was never less than a fully commited performer, and in this song, his vocals are an amazing example of restrained power. He is, of course, a hell of a good singer – something I don't think even his most vehement detractors could deny. Here, not only does he sell the story (and, as I've said, extend the rhythm) but he is able, using nothing more than the tone of his voice, to give the entire song the 'edge' of confined paranoia that makes it more than just a great rhythm line and into a powerful song. How does he do that? Well, therein lies Michael Jackson's greatness.
This song spent an amazing seven weeks at number one on Billboard. It's credited, famously, with breaking the so-called 'colour barrier' on MTV. It launched the most successful album in history (it was the second single, but “The Girl is Mine” was hardly responsible for much of anything regarding Michael Jackson's fame). Ultimately, of course, it remains his signature song and arguably his one greatest hit.