Summer Glau was born on July 24, 1981. She is an American dancer and actress, best known for her role as River Tam in the short-lived science fiction series Firefly and follow-up movie Serenity.

Summer, a native of San Antonio, Texas, was classically trained as a ballerina and also studied tango and flamenco. A professional dancer from the age of 12, Summer relocated to Los Angeles in 2002. Glau appeared in a several television commercials, but her first television credit was a guest role as a ballerina on the 2002 episode "Waiting in the Wings" (episode 3x13) of the television series Angel. There she caught the eye of producer Joss Whedon, who later cast her in Firefly.

Glau has also appeared on the episode "Love Conquers Al" (1x06) of the tv series Cold Case. She also had a small role in the film Sleepover, in which she plays a high school senior named Shelly. In June 2005, she played Tess Doerner, a paranoid schizophrenic Returnee in the second season premiere of The 4400 (episode "Wake-Up Call").

Glau is also one of the stars of the new science fiction film, Mammoth, in which she stars as Jack. The film has completed shooting in Baton Rouge, Louisiana and Bucharest, Romania.