He is of German descent andis head of the Nazi deep science division (H.Y.D.R.A.). He has a god complex which leads him to believe that he is a deity. He plans to overthrow Hitler and take over the world (by destroying all the capital cities of the world). He uses the Asgardian artifact the Tesseract to help him accomplish this.
He was the first of Dr. Abraham Erskine's Super Soldier experiments (Captain America being the second). As the Super Soldier Serum enhances upon all personality traits of the person who it is used upon, it therefore magnifies his insanity. There is also another side effect of the super soldier serum that deformed schimdt into a hideous being with a red skull. Schimdt wore a mask over his face to blend in but half way through the movie Schmidt removes his mask and become 'Red Skull'.
Johann builds a giant plane powered by the Tesseract carrying 8 bombs each set to destroy one capital city in America. Captain America disarms the missiles and fights Johann. Johann overpowers Captain America and shows him the source of the planes power (the Tesseract). Upon touching the Tesseract Schmidt disintigrates.
Johann Schmidt is played by Hugo Weaving.