Sanji is mainly the ship's cook, but is also very skilled at kick battle. While he was a cook trainee as a kid, his ship was asaulted by pirates, he fell off board and was rescued by Red Leg Zeff, captain of the pirate ship that attacked them in the first place. They spent several days on a deserted island waiting to be rescued after the ship-wreck, which ultimately made Zeff eat one of his legs to survive (he had given all the food they had to Sanji). After experiencing hunger first-hand, they decide to open a ship-restaurant, the Baratie, once they are rescued.

And so Zeff became Sanji's master cooking and fighting-wise. When the famous pirate Don Krieg arrives to the Baratie and wants to make it his, Luffy stays behind to help Sanji while Zoro and Usopp go after Nami and the Going Merry. Luffy is determined to make Sanji his ship's cook and doesn't stop his insistence till he complies. Finally, despite the debt Sanji feels he owes to Zeff for saving his life, he leaves the Baratie and joins Luffy, in hopes he can find All Blue, a legendary sea which is said to be inhabited by fish from all over the world.