Michael Douglas won his only acting Oscar from his only acting nomination at the moment for portraying Gordon Gekko in Wall Street.
Michael Douglas is not the true lead in this film, Charlie Sheen is, but he is the most dominating presence of the film, and I would still consider him lead because of that reason. Douglas' performance is a rather influential to his own career, in that he would afterward be cast in many similar how powered business man roles, despite apparently being suggested as being wrong for the part, by some before he was cast.
This performance's influence creates an interesting effect I think because for one I think on viewing this performance after seeing some of his later similar performance, unfortunately takes away the fact that this was an actual a leap of sorts for Douglas in portraying Gekko, and that he does succeed incredibly well in the role, and he is in fact instantly believable as the very powerful businessman Gekko.
Michael Douglas from his first scene he appears as completely in control of his whole business, and Douglas shows that there never is a question of Gekko's sway and power because of Douglas. He personifies the fast moving, quick acting, never stopping corporate manipulator without fault. Douglas simply is the part, Douglas simply is Gekko.
Douglas has the perfect sway in the role, and his basic seduction of Bud into performing illegal deeds for him is convincing, because Douglas has the right charisma, even if a slimy charisma, a perfectly used slimy charisma. Douglas shows his charisma best though in his big "Greed is good" speech, which Douglas has that perfect confidence and dominance, that makes his speech so completely effective.
Stone is not a particularly subtle director or writer, and tends to make his points very obvious, and well to the point, therefore Gekko is pretty simply just evil, doing anything possible to get more money, and make every corporate deal go just his way. Douglas therefore is not allowed all that more development from Gekko besides his evil ways and methods.
Douglas nonetheless gives an effective villainous performance. He makes Gekko's abilities clear, and makes him someone easy to hate. Gekko's eventual defeat near end of the film, is made all the more satisfying because of this though. Douglas portrays Gekko fall well enough, and shows his loss of his control and confidence just as well as he showed it. This is technically a good portrayal of the character, although a performance I more of admit that it is good, than one I really love.