Princess Bubblegum loves (most of) her subjects and has been known to defend them tirelessly when trouble brews. She is very noble and intelligent, perhaps the most intelligent person in the Land of Ooo.

Princess Bubblegum is a highly cultured and educated ruler with an undying passion for science. In "Slumber Party Panic," she attempts to revive the dead Candy People, accidentally creating a horde of zombie Candy People instead. In her dedication, she sometimes drives herself to exhaustion with her experiments. Though ordinarily sweet and good-natured, Princess Bubblegum shows a malicious aspect of her personality whenever she is crossed, as toward the Duke of Nuts for eating all of the royal pudding and supposedly ruining her appearance. Even with her kind disposition, her moral code is not as strict as Finn's. She sometimes says morbid or inappropriate things, such as when Finn picks up a paralysis poison in, she says, "That's paralyzing potion, Finn! Don't touch it, or it'll paralyze you forever!" and then giggles. Many darker things are briefly shown in several episodes such as skeletons cuffed to the walls in hidden chambers. Another example of such behavior can be witnessed as Princess Bubblegum was willing to resort to sabotage and forced sacrifice in order to survive. Also, she displays a non-hesitant willingness to torture Ice King after he infects the Candy Kingdom with a Freezer Burn flu and refuses to assist her in curing them by screaming voluntarily. However, in this case, she does understand what she was attempting to do was wrong, and cries in stress and guilt when Finn exposes this. In "The Lich," she is shown randomly cutting the limbs off of tiny round creatures with scissors and reattaching them in different places when Finn sneaks in, although the creatures show no pain and seem perfectly happy to be reconfigured.