The 'Moonwalk' was originally invented by an artist called 'Casper' (who unimaginatively called it the 'slider'). It later became a worldwide phenomena because MJ executed it (for the first ever time) in the end-closing sequence dance moves of his first ever Billie Jean performance. This happened on 25th March 1983 during the 25th anniversary of Motown. This was staged at the Pasadena Civic Auditorium and called "Motown 25: Yesterday, Today, Forever." The Moonwalk occurs exactly at the same time and in the same way in every Billie Jean performance Michael has done since that one. It is carefully planned to start at a specific beat. It has pre-moonwalk and post-moonwalk moves that go with it. While Michael, over time, has improvised and expanded the Billie Jean performance (the videos below show the improvisations) - the basic structure has remained the same.
Putting on the Hat: The song starts with Michael putting on his hat exactly at the same time the unique multiple layer drums (by the famous Leon Chancler) starts. Then familiar bass guitar/synth is played on top of it and then the chord progressions are created (Sound Engineer Bruce Swedien remixed this 91 times before finally settling on the final version). It is a magical song that he starts creatively. The silence that he creates before putting on his hat is exhilarating. In later performances if Michael is already with his hat ON, then the drums and bass guitar is silenced for a few minutes, only to restart at the exact time he puts it on. The Hat, single-glove, stone studded socks and the jacket are an integral part of the Billie Jean performance.
Pump: After putting his hat on, Michael does - what is called as - the 'pump'. Pump is a simple thrust of the abdomen. The artist is in a bent position and almost looks as if he is watching his crotch thrust out and in.
Swivel: Michael's talent lies in telling the camera men (even if the show is not his) exactly where to position the camera and while dancing he is aware of the various poses he has to strike for those camera angles. If you see all his Billie Jean live performances (Munich 97 and Bucharest especially), camera angles (for viewing in giant screen) totally cranks up the level of his performance. The swivel typically has 3 poses and starts when the drums is accompanied by soft 'shakers'. The first move he does is lift his right leg up, points his finger and toe seemingly towards a person in the orchestra and pauses. This is Pose 1(you can now hear the 'shakers' do a 'chik-chik' sound). Then he swivels and points his right leg to the other side of the stage and points his finger/toe towards someone there. Then he strikes a couple of poses left and right - each with one leg straight and the other leg forming an R shape.
Throw the hat away: Throwing the hat away is done in a very interesting fashion as it almost mimics the onset of a moonwalk. But is a fake. He crosses the legs first and spreads his hand out (I call it the 'no way dude' move) and then he crosses the leg other way to point in the direction he will eventually throw the hat. The way he throws the hat has changed over time. He essentially has two throws: the 'soft throw' that lets him pick it up later and then the inward throw to the crowds. The first throw is always the soft throw. Because he needs the hat for later.
The combing and the start: He never starts singing with the hat on. So after the throw he pretends as if he is taking a comb out, combs his hair and keeps the comb back on his pocket. Don't get distracted by his hands. His legs are striking a pose, which is accentuated by where the cameras are placed. Then he briefly places his hands like a triangle on the crotch and starts singing "she was more like..."
The song: His movements are limited when he is actually singing. The song itself is sung in a mix of falsetto and his regular voice. In this song he introduces a brilliant 'hiccup' way of singing (which he repeats in every other album - 'man in the mirror' and 'who is it' are examples). You can see him do his usual stuff - 'legs sliding towards each other back/forth' and 'hands-in-my-pocket' thing. But he introduces two key moves which he will expand at the closing stages of the song. The 'spin' happens exactly before he sings 'the kid is not my son' (and again before 'do think twice'). He 'spins' and goes into that line. Then he does a bent robot move (which he did till his 'invincible' videos: see video 4 below for that). Here he bends down and moves his hands and face like a robot. This is a common move among African American dancers but he does it with class.
My favorite 'singing move' is when he is really bent down with mike by his side (comes at 2:10 in video 1 below) and sort of does a mini sit-up while singing "on the floor ..". Another favorite moment of mine his jump before singing the chorus "Billie Jean". You haven't seen the moonwalk yet. And he is waiting for the end guitars to start before he shows you that.
The Moonwalk Package (Spin, Moonwalk, Spin, and Toe Stand): The moonwalk package of Billie Jean is stunning for people who have never seen anything like that before. His rhine-stone studded socks and his single glove (it is always one glove when it is Billie Jean) accentuates the slide of the moonwalk. Before the Moonwalk, he shouts a 'hee' (to the left hand side crowd) and 'hoo' (to the right hand side crowd). Crosses his leg to mimic the 'hat throw', bends down and then does a full version of the 'spin'. He then lifts his pants raising them upward, strikes a pose and then begins the slide backwards. The backwards slide apart from giving you massive goose-pimples, almost makes you feel the floor is slippery or fluid. The camera angle makes a significant difference here. The high that you get from watching it done is wonderfully capped by a BIG 'spin' and a toe stand. The toe stand is so difficult that it is almost ridiculous that he even does it. Sometimes he can simply stand on his bent toes for like 3-4 seconds (if he is dancing only with his socks). In the Motown video below he doesn't really get the 'toe stand' right (he said later that he was very nervous about pulling it off) and so quits it soon.
In almost every Billie Jean performance, he does a variation of the Moonwalk after the song ends. Sometimes he Moonwalks sideways (his face front and he moves towards the left - see 3rd video from 7th minute onwards) or does a stop-moonwalk. Where his hand is sort of showing a stop-signal to the front and he moves behind. His stay-in-the-same-place and moonwalk ( 2nd video, minute 6:53) is simply incredible. Blows your mind out.
The End Dance: His Billie Jean performances have changed over time and he began to put a lot of drama in taking out the trade mark single glove, hat and Jacket to whip up the frenzy. This makes your adrenalin pump up like crazy (see the 3rd video beginning). But he also extended the song's ending segment by having a dedicated dance sequence. If you see the second video below, which is his best Billie Jean performance so far: At exactly 6 minute 20 seconds he would reclaim his hat, pretend to clean it up and put on the hat. Then all the lights and other instruments would switch off. Its just drums and a spotlight. Your heart is beating fast not knowing what to expect. Here he would showcase all his newest and best dance moves.
The Robo Revolve/Rotate: This is my most favorite of all his dance moves. He introduced it as part of his Smooth Criminal song sequence in the movie 'Moon Walker' (He had done it once before in 1988 Grammy Awards). Sometimes tears flow if you try to imagine how he really does it. Here, in this move, he stays in a single spot and sort of revolves around himself (see minute 7:30 in Video 3). Its almost as if he splits into two people and one person does a break-dance revolution around the other stand-still person. It looks incredible provided you saw it from the correct camera angle.
Video 1: The Legendary Motown Performance
Video 2: Munich 97 Performance
Video 3: The NewYork performance almost 20 years later.
Video 4: Music Awards
Look at minute 0.50 and 1.12 on his improvised Robot dance.