In high school, she adopted a middle name, Alexis. She learned to speak Mandarin at home and began studying English when she was 5. Liu earned a bachelor's degree in Asian languages and cultures. Liu worked as a waitress at the Ann Arbor Comedy Showcase club circa — She did one commercial. Although she had originally tried out for only a supporting part,  Liu was cast in the lead role.
While queuing up to audition for the musical Miss Saigon in , she told The New York Times , "There aren't many Asian roles, and it's very difficult to get your foot in the door. In , she appeared in an episode of L. Law as a Chinese widow giving her evidence in Mandarin. Liu originally auditioned for the role of Nelle Porter played by Portia de Rossi , and the character Ling Woo was later created specifically for her. Liu's part on the series was originally temporary, but high audience ratings secured Liu as a permanent cast member.
The sequel, Charlie's Angels: Liu also starred with Antonio Banderas in Ballistic: Sever , a critical and box office failure. In a episode of Sex and the City entitled "Coulda, Woulda, Shoulda" she guest starred as herself, playing Samantha Jones ' new client. She also had minor roles as Kitty Baxter in the film Chicago and as a psychologist opposite Keira Knightley in the thriller Domino. In Liu appeared in Code Name: The Cleaner ; Rise , a supernatural thriller co-starring Michael Chiklis in which Liu plays an undead reporter  for which she was ranked number 41 on "Top 50 Sexiest Vampires" ;  and Watching the Detectives , an independent romantic comedy co-starring Cillian Murphy.
She made her producer debut and also starred in a remake of Charlie Chan , which had been planned as early as Elementary is an American Sherlock Holmes adaptation, and the role Liu was offered is traditionally played by men. She also has played police officer Jessica Tang on Southland , a television show focusing on the lives of police officers and detectives in Los Angeles as a recurring guest actor during the fourth season. She is also part of the cast in the upcoming post-apocalyptic thriller Future World , directed by James Franco and Bruce Thierry Cheung.
The movie, titled Meena, was based on a true story, about an eight-year-old Indian girl who is sold to a brothel. The movie was screened in New York City in In , she produced and narrated the short film The Road to Traffik, about the Cambodian author and human rights advocate Somaly Mam.
This led to a partnership with producers on the documentary film Redlight. I went into shell-shock. It was pretty traumatizing. She has stated, "I'm into all things spiritual—anything to do with meditation or chants or any of that stuff. I studied Chinese philosophy in school. There's something in the metaphysical that I find very fascinating.