Jordan Baker is Daisy’s friend, whom Nick has a short-lived relationship with.
She is a famous professional golfer, slender and athletic in appearance (p. 16). We soon learn from Nick that she has a strong habit of dishonesty - she allegedly cheated in an important golf tournament (p. 58) and she generally enjoys lying to and misleading others.
Just like the Buchanans, she is described as a rather shallow and uncaring person. She is intrigued by scandals and always eager to learn more about people’s affairs and dark secrets. She freely admits to being a terrible driver, but suggests it is other people’s responsibility to get out of her way (p. 59), which also reflects her uncaring and reckless nature.
Her role in the novel’s narrative is mostly limited to the sidelines, though she does play a role in setting up the first meeting between Gatsby and Daisy, acting as a communicative link between Gatsby and Nick. More indirectly, she also serves as symbol of Nick’s fascination with the lifestyle of the East.