As Emperor, Palpatine rules the Galactic Empire in the Star Wars universe. For his wisdom, see anger. Also see Chancellor Palpatine above.
We first meet Palpatine as a senator in the Old Republic. The Star Wars website says he served "during a time of corruption, social injustice, and bureaucratic abuses."
During Episode I, Palpatine manuevers to replace the incumbent Chancellor Valorum for leadership of the Galactic Senate. A decade later, during Episode II Palpatine is awarded "emergency powers" which he promises to relinquish as soon as the 'emergency' ends. However the emergency continues during the 3 year span of the Clone Wars.
During Episode III he anoints himself Emperor, permanently.
During Episode IV the renamed Imperial Senate is disbanded and Palpatine becomes the unquestioned ruler of the Galactic Empire.
The Emperor resides within the Imperial Palace on the planet Coruscant. It dwarfs the nearby Senate and Jedi Temple.
The Emperor is a Sith Lord, steeped in the dark side of the force. He uses this power to twist and corrupt the Old Republic, and eventually reaches into its heart to even twist the Jedi themselves. Obi-Wan's young Padawan Anakin is taken from the path of the Jedi by Palpatine, who remakes Anakin into the Dark Lord of the Sith, Darth Vader.
I'm sure most of you (except people who have never seen Star Wars) know the rest.
But here's something I bet you didn't know ... according to IMDB cast listings, Palpatine's first name is ... Cos. How strange is that? I wonder if it's caws or cohs... If it's like Bill Cosby then ...
Hey, you Sith Lords! Get outta that Jell-o tree!
Note that Wikipedia says this name is non-canon, and the name came from an early script draft.