Felicity Megan Smoak was born to Donna Smoak and an unnamed man. When she was very young her father abandoned her and her mother. She reputedly lived in Las Vegas with her mother until she went to college.
Felicity has a Jewish background. She has mentioned that she is Jewish to Oliver Queen in Year's End when he wishes her a Merry Christmas and she replies, "I'm Jewish," and a second time to Barry Allen in Three Ghosts, when he asks what her holiday plans are and she responds "Lighting my menorah". In addition, when she sees John and Lyla's new baby, she said "Mazal Tov", a Jewish phrase for congratulations. At Sara's burial, she performed a jewish custom by throwing dirt onto her coffin.
At a young age, Felicity became interested in computers, claiming to have been building them since she was 7. However, she was always fearful that she would wind up as a cocktail waitress like her mother and worked hard to escape from her circumstances. Due to their differing personalities, Felicity had a strained relationship with her mother. When she was 19, Felicity was ranked 2nd in the National Information Technology competition.