He's the guy you love to hate because there really is no redemption for him. As the commander of the Death Star in A New Hope, he threatens to destroy Princess Leia's home planet Alderaan if she doesn't tell him the location of the Rebel main base of operations. She names the planet Dantooine (which is false) and he uses the Death Star to destroy the planet anyway, in order to make an example out of her.
But, as it always turns out for the bad guys, he is ultimately killed when the Death Star blows up the first time. A younger version of the character appears in Revenge of the Sith standing next to Darth Vader and Emperor Palpatine as they watch the Death Star being built.
With the help of CGI, since original actor Peter Cushing passed away in 1994, he pops up in Rogue One as a constant thorn in Orson Krennic's side.
