Once a Senator in the Old Republic, instrumental in the birth of the Empire. As Emperor, the supreme ruler of the Empire. A student in the ways of the Dark Side of the Force. He was a xenophobe, though he used aliens when it suited him. Through his use of the Dark Side, he gained a large body of knowledge on the use of clones to become virtually immortal. The fresh supply of new bodies ensured that the destructive power of the Dark Side never killed him.

Early in his tenure as Emperor, Palpatine recognized the strength of Anakin Skywalker, and twisted the young Jedi to the Dark Side of the Force. The Emperor used Sith magics to recover Anakin's body, following a duel with Obi-Wan Kenobi, and revive it. The new spirit discarded its old name and became Darth Vader. Palpatine taught Vader in the ways of the Dark Side, but was always wary of the possibility that Vader might have had children.

Palpatine ruled the galaxy as Emperor for nearly 25 years, until he was killed by Darth Vader aboard the second Death Star, over the Forest Moon of Endor. Palpatine's body was consumed by the fierce power generators in the battle station, but his spirit survived. It took the disembodied Palpatine so long to reach the planet Byes that he was nearly drained of any power in the Dark Side.

Once on Byss, though, he was able to contact Sate Pestage, who readied a new cloned body for the Emperor. Palpatine spent years recovering his powers in the Dark Side, all the while watching the Empire crumble under the sheer luck of the New Republic. He had hopes for Grand Admiral Thrawn, but the alien's death only helped Palpatine gain more power. When he emerged from hiding on Byss, he sought to retake the galaxy using World Devastators. He was also trying to turn Luke Skywalker to the Dark Side, which he nearly succeeded in doing. However, the presence of Luke's sister, Leia Organa, and her unborn child pulled Luke back to the Light Side. Together, they turned the Emperor's rage back on himself, and destroyed yet another incarnation on the evil Emperor.

Since this last body was killed on Byss, Palpatine had an easier time placing his spirit into a new clone. However, Luke managed to destroy all of the remaining clones Palpatine had ready for use, and so when his body began to deteriorate, he started searching for Anakin Solo again. He quickly began launching new attacks against the New Republic, this time with a weapon known as the Galaxy Gun. Skywalker enlisted the aid of the Ysanna - a race of Force-sensitives descended from ancient Jedi stock - as well as the assistance of Empatajayos Brand, to confront the Emperor on Onderon. There, Palpatine's dying body tried desperately to reach Anakin Solo. Brand intervened, though, and consumed the Emperor's spirit within his own. Both Brand and Palaptine died on Onderon.

Later, during the rise of Second Imperium, a group of former Imperial Royal Guards began using their experience with Palpatine to actually pretend to be the Emperor reborn. Using carefully spliced holovid segments, they were able to project a perfect image of the Emperor, and were also able to synthesize speech from recordings. Whenever they traveled, they used droids to carry a large isolation chamber, which ostensibly housed the reborn Palpatine. Their ruse fooled Brakiss and the leaders of the Shadow Academy, until they were discovered in the aftermath of the battle over Yavin 4.