Jules Winnfield

Jules Winnfield is the deuteragonist of Pulp Fiction. Initially he is a Hitman working alongside Vincent Vega but after revelation, or as he refers to it "a moment of clarity" he decides to leave to "Walk the Earth." During the film he is stated to be from Inglewood, California.

History
Riding in a car on the way to a hit —both wearing dress suits—, Vincent was relating his impressions from his stay in Europe concerning the possession of dope and the laws in Amsterdam. He was impressed on how in European cinemas beer is served in glass, how the Quarter Pounder burger is called Royale with Cheese in Paris (and Big Mac is called "Le Big Mac") and how in Holland the French fries are eaten with mayonnaise instead of ketchup.

On their way to the job, Jules was narrating him about Marsellus' new wife, Mia Wallace and the trouble with Antoine Roccamora when he gave foot-massage to Mia. Jules found it too much, while Vince insisted that it was 'laying hands in a familiar way', something that you wouldn't do for example to another man. He proved his point that although you don't mention it, you know that foot-massage has something special and sensual.

Vincent was especially worried hearing about Roccamora, since he was tasked to take care of Mia while Marsellus was off to Florida. They conclude their banter and "get into character", which soon involves executing Brett who has transgressed against their boss, gangster Marsellus Wallace in dramatic fashion after Jules recites a baleful "biblical" pronouncement, and retrieve the briefcase.

Divine Intervention/The Bonnie Situation
They are nearly killed themselves when a third student emerges from the bathroom and fires six shots, all of which narrowly miss. Back in the car, Vincent gets into a disagreement with Jules who is convinced they have been saved by a miracle.

Brandishing his pistol while talking, Vincent accidentally shoots and kills Marvin the informant who led them to the college students. Blood and brain matter are sprayed all over them and the inside of the car.

They take refuge with Jules' friend Jimmy Dimmick and call Marsellus, who sends his personal problem solver Winston Wolf. Wolf helps them quickly get rid of the car and the body. The two hitmen, now dressed in colourful t-shirts and athletic shorts borrowed from Jimmy, then have breakfast in a Hawthorne coffee shop where Jules tells Vincent he is going to quit working for Marsellus and leave "the life" of being a hired killer.

The Diner
When Vincent goes to the men's room, a young couple (Ringo and Yolanda) randomly try to rob the coffee shop (the film's non-linear beginning) and demand the briefcase from Jules, who winds up holding one of the robbers at gunpoint in a Mexican standoff. When Vincent gets back, Jules tells him to hold off, then tells the robber that to instead of killing him and his girlfriend, he is buying his life for $1500. Jules then explains to the robber that he was going to forsake his life of crime.

Vincent and Jules leave the coffee shop ahead of the police and go to Marsellus' Inglewood strip club to give him the briefcase.

Vincent Vega and Marsellus Wallace's wife
After the coffee shop ordeal, Vincent and Jules go to Wallace's hideout to return his briefcase to him. Jules goes to urinate and his appearance in the movie ends.

Trivia
Jules explains that he recites a Biblical passage, Ezekiel 25:17. He seems to be somewhat of a spiritual person, refraining from eating pork (complying to Kosher or Halal), resembling a pastoral preacher while reciting the passage, and is eager to attribute his survival to a miracle.

There are even theories that Winnfield turns up as a hobo in the Breaking Bad episode "Blood Money" but this time Wayne Dehart is acting the role of Jules and receives a bunch of money from Jessie Pinkman when he says "take it" and the homeless man, with a shopping cart full of plastic bags that could be Jules, takes the money. In the end of Pulp Fiction, Jules even talks about "walking the earth" to Vincent, who at first assumed that Jules was going to be a bum.

At the end of Pulp Fiction Jules states that he wants to be a lone drifter that walks the earth. Samuel Jackson plays a piano playing drifter in Kill Bill Vol 1 using the name Rufus and references being in a gang prior to playing the piano in the chapel.

The part of Jules Winnfield was originally to be played by Paul Calderon but Samuel Jackson liked the part so much he flew out to California to audition for the part again to ensure that he got the part.

Source
Much of the text comes from a deleted Wikipedia article.