who portrayed it in the series?
Chyler Leigh
Lexie Grey
Alexandra Caroline Grey, M.D. is a fictional character from ABC's medical drama television series "Grey's Anatomy", portrayed by actress Chyler Leigh. 
what happened to lexie grey in season 8 Her plane crashes and she dies while fantasizing about the future that she and Mark could have had together who is she actually? A fictional character from medical drama television series "Grey's Anatomy"
wiki:9163232
Lexie Grey [SEP] Introduction
Alexandra Caroline Grey, M.D. is a fictional character from ABC's medical drama television series "Grey's Anatomy", portrayed by actress Chyler Leigh. Created by series producer Shonda Rhimes, the character is introduced in season three as the titular protagonist's younger paternal half-sister. She transfers to Seattle Grace Hospital as a new surgical intern after her mother's sudden death, and is eventually named a surgical resident in season six. Leigh was originally contracted to appear for a multi-episode story arc but ultimately received star billing from seasons four to eight. She has also reprised her role as Lexie on the spin-off show "Private Practice".