<Tr> <Th> Significant other (s) </Th> <Td> Mark Sloan Alex Karev Jackson Avery </Td> </Tr> <Tr> <Th> Relatives </Th> <Td> Derek Shepherd (brother - in - law, deceased) Zola Grey Shepherd (adoptive niece) Derek Bailey Shepherd (half - nephew) Ellis Shepherd (half - niece) Laura Thompson (niece) </Td> </Tr> <P> Alexandra Caroline "Lexie" Grey, M.D. is a fictional character from ABC's medical drama series Grey's Anatomy . Created by series producer Shonda Rhimes, the character was portrayed by actress Chyler Leigh from the third through eighth seasons . She was introduced as a surgical intern in season three . Serving as Meredith Grey (Ellen Pompeo)'s half - sister, Lexie transferred to the fictional Seattle Grace Hospital after her mother's sudden death, and was eventually named a surgical resident . Leigh was originally contracted to appear for a multi-episode story arc, but received star billing in the fourth season . </P> <P> The character's focal storyline involved her romantic relationship with plastic surgeon Mark Sloan (Eric Dane). She sustained life - threatening injuries after an aviation accident in the eighth - season finale, which ultimately ended in her death . The hospital is later renamed Grey - Sloan Memorial Hospital in her memory . Lexie's death resulted in mixed critical feedback, and the reason given for her departure was Leigh's desire to spend more time with her family . </P>

When does lexie come on grey's anatomy