Booster is a man who resides in Booster Tower, located in Booster Pass. He is the seventh generation of Boosters, as indicated by a picture of his ancestors. He spends his time playing with his three Snifits, often involving a train. He is a bit eccentric to the point of insanity, and his antics can be harmful to others, but for the most part he means no harm. He appeared in Super Mario RPG: Legend of the Seven Stars.
When Exor crashed through Bowser's Keep, he sent Mario, Princess Peach, and Bowser flying in different directions. Peach landed at Booster Tower, where Booster tried to force her to marry him. Mario witnessed his Snifits attempting to catch a beetle, and, hearing that Peach was at Booster Tower, headed there with Mallow and Geno to rescue her. There, they joined forces with Bowser, who was out to regain his castle from Smithy. The four made their way through the castle. Booster seemed to not realize who Mario was, and threw Bob-ombs at him in an attempt to eliminate him (although when Mario left, Booster said he just wanted to have fun with him). Eventually they reached Booster's room (as usual Mallow, Geno, and Bowser seem to disappear when not in battle, but can appear at any time they want). Mario hid behind the curtains when Booster and his Snifits entered, and the Snifits began looking for Booster's Mario doll, looking behind the curtains while Mario avoided them, until all four were opened at once. At this moment, Booster saw the Mario doll on top of the curtains, and Mario got it down for him. Booster left with his Snifits and Peach.
As Mario followed him onto the balcony, his two jesters, Knife Guy and Grate Guy attacked them, but Mario defeated both and chased after Booster on Booster Hill until they reached the town of Marrymore. Booster kicked Raz and Raini (who were trying to get married) out so he could marry Peach. Mario snuck in through the secret entrance, and he and Bowser broke through the door to crash the wedding. As they were about to leave, Chef Torte and his apprentice entered with a cake they made for the wedding. Furious that no one was going to eat it, they fought Mario, but suddenly the cake came to life. Mario and his partners defeated Bundt, and Booster ate him by swallowing him whole. He found the cake to be quite delicious, and officially declared the wedding over, and returned to his tower with his Snifits.
After Mario defeated Valentina, her assistant Dodo flew away with her, but they fell on Booster Tower. Booster tried to marry her, and was able to win her heart (although at times he seemed a bit afraid of her afterward). After Smithy's defeat, Booster and Valentina got married at Marrymore.
If Booster finds Mario enough times before all four curtains are opened at once, he will fight him. He is quite hard, as his Snifits must be defeated first, then him. Booster has 800 HP, 75 ATK, 55 DEF, 1 Magic attack, and 40 Magic Defense. He uses Spritz Bomb and Loco Express for magic attacks. He is weak against jump attacks. If Mario wins, he will get a Flower Tab.
His Psychopath thought is "This is like realizing you're outside without your clothes on!"
- Booster resembles Mario's rival, Wario
- The password for the door to his balcony is the same as the name the player chooses for the file.
- Booster's theme song sounds similar to a scene from Pulp Fiction, near the end of Part 2 (The Gold Watch).