Summer

Summer Roberts (played by Rachel Bilson) – (Seasons 1 – 4): The socialite of the four main teen characters (Ryan, Seth, Marissa and Summer). She is the love interest of Seth, and best friend to Marissa. She is the daughter of Dr. Neil Roberts. Initially Summer is the "bitch" of the group but it soon became clear this is a cover for her own insecurities. Her mother left when her parents divorced after her mother abandons them and she has had no contact with her since. Her stepmother, nicknamed the "step-monster", a lazy woman with a suggested drug problme is mentioned few times throughout the series and is shown only once from behind in season 4. When Seth sails to Portland, Summer finds a new love interest, Zach. On the way to be maid of honor in Zach's sisters' wedding in Italy, Summer leaves Zach at the airport realizing that she is meant to be with Seth. She and Seth believe she is pregnant in the fourth season and they planned to get married. After they find out that she isn't, they break off the engagement, though not their relationship. Six months after the earthquake, Summer and Seth go their separate ways, allowing Summer to pursue her environmental interests, which she develops after the death of her best friend, Marissa. The two get married sometime in the future.