God created him.
Eze 28:
13) Thou hast been in Eden the garden of God; every precious stone was thy covering, the sardius, topaz, and the diamond, the beryl, the onyx, and the jasper, the sapphire, the emerald, and the carbuncle, and gold: the workmanship of thy tabrets and of thy pipes was prepared in thee in the day that thou wast created.
(some people do not believe that Isa 14 and Eze 28 are talking about Satan. I do.. )
God created both angels and humans with free will. Satan chose to try and usurp the throne of God.
No.
God is righteous and just. He originally -gave- dominion of this world to Adam and Eve. It was -theirs- to do with as they pleased. When they sinned, that dominion was -transferred- to God's arch enemy, Satan, and Satan still has that dominion. Satan gaining control of the world was a legal result of the sin of Adam and Eve. The whole creation was disrupted when Satan gained control of things (Rom 8:19-22). While the control that Satan now has is certainly distasteful, it is legal. Because God is righteous and just, He cannot just say "whoops, I did not mean for that to happen. You cannot do that, Satan".
Satan still has access to heaven, where he continually accuses people before God (Rev 12:10). One day soon (I believe), Satan will be kicked out of heaven, and God will send Jesus Christ to earth to fight Armageddon and take back control of the world. Then is when the dominion of this world will be taken from Satan.
I believe that understanding that God is righteous and just, and that God created both angels and humans with genuine free will, helps make it a little less complicated.
People who believe that "God is in control" of everything that happens will not accept this explanation.