Ron Weasley hails from one of the oldest pureblood Wizarding families, but unlike many other purebloods the Weasley's have not had any dark associations. They are relatively poor and Ron is a child of hand-me-downs. Ron has six siblings, five older brothers (Bill, Charlie, Percy, and the twins (Fred and George) and a younger sister, Ginny.
Being one of many makes him strive for attention in some respects, making him at times jealous of Harry's fame and envious of the intelligence of the pair's best friend, Hermione Granger. Ron is portrayed as the least special of his siblings, with no above-average skills, which leads him to try harder at most things than any of his friends or family members.
J.K. Rowling describes Ron as insecure and immature throughout the books. Still, Ron plays a large part in all of Harry's adventures. In the first movie, for example, he sacrifices his chess piece (and consciousness) to allow the other players to move on and save the day. In later films Ron becomes key in organizing the students to protect the Hogwarts school from the Dark Lord .
Sometimes, however, the tensions and jealousies get in the way of him being an asset to the force of good. He doesn't always believe Harry's theories, such as not agreeing with Harry that Draco Malfoy is a Death Eater in the most recent movie, 'Harry Potter and the Half-Blood Prince,' or turning his back on Harry for much of the 'Goblet of Fire' movie because he believes Harry has entered a tournament, even though Harry denies the fact.
Ron also has one of the most defined and longstanding romantic plot lines -- a budding romance with Hermione. Although fans initially couldn't decide whether they wanted a romantic relationship between Hermione and Ron or Hermione and Harry, Ron and Hermione have become author J.K. Rowling's chosen pairing. Over the course of the stories, Ron has displayed considerable jealousy about Hermione's other suitors, but like any teenage boy he's been unable to realize his feelings and actually understand that Hermione likes him just as much. In the final films their relationship will be both tested and solidified.