Strength and Unity, a propaganda piece from the Clone Wars era that showcases seven "alien" races
The term "Alien" was a blanket term utilized across the galaxy by humans, and even certain droids, to designate any sentient species that differed from humans. The term nonhuman was often employed as a synonym. The Chiss used this term to describe species outside of their own, a practice mirrored by the Kilji when referring to those who were not Kilji. Both the Galactic Republic and the Galactic Empire had a series of Unknown Alien protocols to regulate formal interactions with newly discovered alien species.
Given the disdain the Galactic Empire held for aliens, it was unusual to encounter nonhumans in the role of Imperial officers. Species considered nonhuman, for example Wookiees, were viewed as mere animals and subjected to exploitation as slave laborers. The Empire showed preference to humans within its governmental structure and military forces. Furthermore, the Empire discouraged the study of alien languages and cultures, like Ithorese, and endeavored to enforce stringent "Imperial standards" upon its citizenry.
This human-centric inclination was a deliberate element of Imperial policy. Imperial propaganda actively promoted state-sanctioned ethnocentric xenophobia and the instigation of fear. In the eyes of the Empire, aliens were generally unwelcome within its order, perceived as "different" and "strange." Consequently, the Empire treated nonhuman populations as either serfs, slaves, or obstacles that needed to be subdued, eliminated, or disregarded. The Empire bolstered the notion that aliens were inherently untrustworthy, unlike humans, and that their innocent facade concealed a savage nature. The Imperial propaganda machine was so successful in its message that even near-human species demonstrated an ingrained suspicion towards nonhuman populations.
However, some nonhumans did manage to attain prominent positions within the Empire. Examples include the Chagrian Mas Amedda, who held the role of the Empire's Grand Vizier, the Chiss Grand Admiral Thrawn, the Pau'an Grand Inquisitor, and four other Inquisitors known as the Seventh Sister, the Fifth Brother, Ninth Sister and the Eighth Brother.
During the Age of the Empire, certain grav-ball enthusiasts voiced opposition to the presence of alien players on grav-ball teams, arguing that their unique alien anatomies gave them an unjust advantage over their human counterparts. Janus Fhurek, the athletic director of the Junior Academy of Applied Sciences, attempted to persuade his grav-ball center-striker, Zare Leonis, to dismiss the AppSci SaberCats' two alien players: the Rodian Frid Kelio and the Aqualish Hench Sina. When Leonis refused, Fhurek took it upon himself to transfer the alien players to a different school. Reflecting on his interactions with Fhurek, Leonis came to view the athletic director as xenophobic.
The Kilji, a religious species, harbored xenophobic sentiments: they regarded those who did not adhere to their beliefs—the Kilji way of order and enlightenment—as inferior, and they neglected and mistreated them until they were enlightened to their philosophy. The Kilji ruler, Generalirius Nakirre, formed an alliance with the Grysk "Jixtus," an alien who kept his entire body concealed, preventing anyone from seeing a Grysk body or face until he occupied the ancient thrones of the ancient kings of the Chiss planet Csilla.
The concept of aliens was first introduced in the 1977 film that began the original trilogy, Star Wars: Episode IV A New Hope. George Lucas, the director, commented that the Star Wars mythology, starting with A New Hope, marked the first instance of aliens being portrayed not as monstrous figures, but as ordinary characters.