According to Eiichiro Oda, Sanji most resembles a duck. He is identified by the color blue, and smells of seafood and cigarettes.
Sanji is the Straw Hat crew's chain-smoking chef, whose dream is to find 'All Blue', a legendary ocean which contains all the fish in the world. He takes great pride in the meals he makes and considers them works of art. Sanji is also a very skilled fighter, who uses a fictional martial arts style called 'Red Leg' that makes use of only kicks. Sanji states that this is because a chef's hands are his prized possession and should not be risked in battle. He was trained by the once infamous pirate Red Leg Zeff, who was a chef himself and once battled in the grand line. In battle, he typically manipulates things from off-panel and then appears in the front lines at a very crucial moment. This has led to a running gag in the series centering around Sanji never being recognized by the Straw Hats' enemies, a joke culminating in the release of his first wanted poster. Sanji was born in the North Blue, but grew up in the East Blue. His left eye is always covered by his hair and almost always remains unseen.
Nine years before the Straw Hats meet him, a young Sanji is working aboard a floating restaurant as as a trainee chef in the North Blue. Even at this early point in his life, he dreams of finding 'All Blue'. This makes him somewhat of an outcast among the other chefs, who regard the sea as nothing more than a legend told to small children. The cruise ship is attacked by the pirate "Red leg" Zeff, and the ship sinks during the ensuing battle. Sanji is surprisingly rescued by Zeff, and they both wash onto the shore of a nearby desolate island. The island was completely made of rock. Its edges were too steep to climb and they had no way of getting nutrition. With almost no food left, Zeff splits the remaining rations with Sanji, keeping a large sack for himself since, as he tells Sanji, he is an adult with a larger stomach. He tells Sanji to wait for a rescue ship on the other side of the island. Many weeks pass, and with Sanji having finished his rations much earlier, he decides to steal Zeff's food. He tells the old man not to interfere or he will kill him, and slashes the large sack of food open, only to discover that it's just a sack of treasure. Sanji then notices Zeff's missing leg, and realizes Zeff had no food for the entire time they had been stranded and was forced to eat his own leg. Sanji tearfully asks why Zeff would do such a thing, and Zeff explains to him that they share the dream of finding 'All Blue'. The two are rescued some time later, and Zeff uses his treasure to establish the Baratie, a floating restaurant in the East Blue with Sanji as his sous-chef. Due to this ordeal, Sanji will never refuse someone a meal and becomes angry when someone wastes food.
In the Anime, Zeff did not eat his leg, but he cut it off in an attempt to save Sanji from drowning.
Sanji is one of the most popular One Piece characters, as he ranked third in a recent Japanese fan poll.
Sanji has a strong sense of chivalry, and he will never harm a woman, no matter what. As said by himself, he will never kick a woman even if he dies because that is how he was brought up. Sanji also seems to keep this code regardless of a woman's appearance. After the events of Enies Lobby, Sanji obtained a bounty poster, but the cameraman kept the lenscap on making the photo completetly black so a rough sketch of his appearance was made. Recently, in the Flying Fish Riders Arc, Iron-Mask Duval tried to wreak revenge on him because of his appearance being the spitting image of his bounty poster, making Sanji have his first enemy with a grudge.
Eiichiro Oda has said that the spiral end of Sanji's eyebrow channels the 'circular energy' of the universe.
In the FUNimation television broadcast of the anime, Sanji's cigarettes are removed. A FUNimation spokesman has stated this is due to Cartoon Network's broadcast standards, and the cigarettes will be retained in the uncut DVD releases.
Powers and abilities
Sanji is a powerful martial artist with superhuman strength, speed, and endurance. He is considered by the Straw Hat crew to be one of their strongest fighters. Sanji has mastered Red Leg, a fictional unarmed martial art which strictly uses the lower body and legs in combat similar to capoeira. Sanji's leg strength is great enough to smash through rock and defeat monstrous beasts in a single blow. Oda rates Sanji's kicking power as enough to shatter twenty one wooden baseball bats in one kick Sanji is also shown to be very acrobatic, using flips and handstands in his fighting. His fighting style's name is taken from the alias of "Red Leg" Zeff, Sanji's mentor and developer of the style. Red Leg possesses a variety of special attacks, most of which are simply exceptionally powerful kicks. These techniques are named in French, and generally refer to the part of the body Sanji is attacking.
Sanji's most powerful ability is Diable Jambe, which involves rotating at high speeds, heating his leg via friction until it glows red-hot. This powerful ability enhances his kick and literally burns his opponent when it connects, though it does no damage to Sanji. Oda states this is because Sanji's heart burns even hotter.
A unique attack to Sanji would be his beautification attack (Parage Shot!), which he demonstrated against chef Wanze. With several kicks to the face, Wanze's face changed to resemble one would expect from the protagonist of a shojou manga. This skill is shown again many chapters later on Iron Mask Duval.
As an expert chef, Sanji is capable of preparing almost any dish imaginable, while holding to a strong sense of the aesthetics of cooking. Sanji is also skilled in fighting with kitchen knives, as demonstrated against Cipher Pol chef Wanze. Though lacking the power and technique of Roronoa Zoro with a bladed weapon, he is able to make very accurate cuts.