Summer Lyn Glau (born July 24, 1981) is an American dancer and actress, known for playing River Tam in the short-lived science fiction series Firefly and follow-up movie Serenity, and for playing Cameron in the series Terminator: The Sarah Connor Chronicles...Glau was born in San Antonio, Texas, where she grew up with her two younger sisters, Christie and Kaitlin. Her mother is a schoolteacher and her father a general contractor.
Glau received a scholarship to a ballet company and was home-schooled from grades 3 to 12 to accommodate her ballet training. After a serious ankle injury finished her dancing career Glau took time off from dancing to visit friends in Los Angeles, where she auditioned for several television commercials. Glau later moved to Los Angeles to pursue a more active acting career. She is of Scotch-Irish and German descent.
source: wikipedia
