Lemmy debuts in Super Mario Bros. 3, where he and the other Koopalings aid Bowser in his conquest of the various realms of the Mushroom World. Lemmy takes over Ice Land, stealing the magic wand of its king and turning him into a seal in the Family Computer and Nintendo Entertainment System versions, or a Monty Mole in the Super Mario All-Stars and Super Mario Advance 4: Super Mario Bros. 3 remakes. Lemmy is found and battled in the cabin of his airship at the end of World 6. He rides a magical ball around during battle, and uses his wand to summon additional balls; once summoned, they do not disappear. The balls are obstacles and can be jumped on, but will shrink Mario or Luigi or make them lose a life if they are touched in any other way. At first, he balances in place on the right side of the room, conjuring balls. Unlike the other Koopalings, when jumped on and withdrawing into his shell, Lemmy stays in one place on his ball instead of jumping around. After coming back out of his shell, he begins running erratically around the room while summoning more balls. Being stomped three times defeats Lemmy, allowing Mario to return the magic wand to its king, and also turning the king back to normal.

In Nintendo Power coverage for Super Mario Bros. 3, Lemmy is nicknamed the Clown Prince of Koopas, a likely reference to one of the nicknames for Batman's archnemesis, the Joker (the Clown Prince of Crime), itself a pun on the term for the heir apparent of monarchies (Crown Prince).