Summer Glau is an American TV actress from San Antonio, Texas. She is the oldest of three daughters. Her father and mother worked as a general contractor and a school teacher, respectively. When she was younger, Summer was a professional ballet dancer. Her ballet training schedule required her to be home-schooled by her mother from Grades 3 to 12. She secretly wanted to become an actress.

When she was older, Summer was forced to take a break from dancing due to a foot injury. She began to act, appearing in various commercials and theatre productions. Then when she finally made it on a TV show as a guest star in an episode of Angel, writer/producer Joss Whedon took notice. Whedon ended up casting her as River Tam, in his sci-fi series Firefly.

She also appeared as a guest in episodes of Cold Case and CSI and made a short appearance in the movie Sleepover, before reprising the role of River Tam in the Firefly sequel-movie Serenity. After that, Summer landed recurring roles in both The Unit and The 4400 and leads in the movie The Initiation of Sarah and made-for-television movie Mammoth.

In 2008, she began her regular role as Cameron, a female cyborg, in the FOX series Terminator: The Sarah Connor Chronicles.