Dr. Eggman is an evil and megalomaniacal genius who is constantly planning to take over the world and those beyond his. Showing contempt for how "filthy" and "irregular" the world is, he views himself as obligated to perfect it by ridding it of what he deems as imperfections, including hunger, disease and, above all, free will. Arrogant, raucous and explosive, he believes that he is bringing peace and unity to the world under his brilliant leadership. He also does not accept the world as it is as a whole. Instead, he wants to transform it to his liking and set up terrifying amusement parks like Eggman Land. His reasons for doing so is that he simply likes amusement parks and does not care about their effectiveness; all he wants is to control precisely what his enemies experience in their last moments. Eggman likewise prefers to show up and claim responsibility whenever he is carrying out his villainous deeds and make himself known to his enemies after he comes back from a defeat; as put by Sonic, subtlety is not Eggman's forte.

Eggman has a tendency to often personalizes his works by plastering his face or overall image all over his creations, like the Faceship. Other times, he focuses his work around a specific theme. He also uses every situation he can get to personally destroy his enemies and move closer to the realization of his ambitions, as well as evade every instance where he is supposed to take responsibility for his actions and the consequences that follows as a result of his half-baked schemes. Having little to no honor either, Eggman is likewise depicted as having almost zero compassion and regard for others than himself. Cunning and lying, he will use and manipulate his minions and subordinates however he sees fit without a pang of remorse, not caring about ideals such as loyalty. He similarly uses them as tools that he can get rid of at any time after they either fail him or have served their purpose. Noticeably, he tricked Rough and Tumble into turning themselves into Zombots despite the skunk brothers being "perfect minion fodder" for him and that he owed them a deal for helping him back to his senses while he was an amnesiac. He similarly seeks to enslave the whole world with fear. He is also shown to be extremely ungrateful, as some of his first victims during the Metal Virus plague were the people of Windmill Village who took care of him while he was suffering from amnesia.