An ambitious Imperial officer, Piett rose through the ranks to captain and was assigned to the Super Star Destroyer Executor, Darth Vader's flagship. There, he chafed at having to serve under the foolish, vainglorious Admiral Ozzel. When Vader strangled Ozzel, Piett was granted a battlefield promotion to admiral -- and given a grisly warning of the penalty for failure. Miraculously, he survived his time as Vader's underling, but died when a Rebel starfighter destroyed the Executor's command bridge.
Piett feared Darth Vader, having seen firsthand that his subordinates often paid for their shortcomings with their lives. When the Millennium Falcon escaped at Bespin, Piett expected to die -- but a preoccupied Vader spared his life. Piett never again trembled in Vader's presence: The Sith Lord's whims would determine Piett's fate, so he might as well do his duty as best he could.
Captain Piett saw Admiral Ozzel as the embodiment of everything he despised in the Imperial Navy: The man was pompous and self-satisfied, unimaginative and arrogant. When Vader killed Ozzel, Piett celebrated both his own promotion and the removal of an incompetent commander.
Piett was disgusted when Vader interrupted the search for the Millennium Falcon to hire a gang of bounty hunters, grumbling that the Empire had no need for such scum. Bossk overheard the admiral's opinion and voiced a rather foul dissent.
The mighty Executor represented the pinnacle of power in the Imperial Navy, dwarfing the Star Destroyers serving as her escorts. Surveying the sweep of her bridge, Piett could only marvel that his Naval career had attained such heights.
At the Battle of Endor, Piett had Admiral Ackbar's fleet trapped, but the Emperor ordered him to hold position instead of attacking. Frustrated by orders that made no sense to him, Piett could only stand by and wait to see what the Emperor had in mind for the Rebels.