Born in Munich, Germany, to an American mother and German father, Banks moved to Britain at the age of four, and then to the Los Angeles suburb of Simi Valley in California, United States when she was seven years old. Her father still lives in Germany. She moved out of her mother's house when she was sixteen years old, taking her fourteen year old sister with her. She got custody of her sister when she turned eighteen. She modeled as a teenager, including a cover of Teen Magazine. She held various other jobs before entering the adult industry; making pizza, clerk at an arts and crafts store, file clerk, and secretary.
At age 21, in August 1999, she responded to an ad in the newspaper to do nude modeling for adult magazines. The photographer put her in a pornographic film. Her first film was University Coeds 18, for Dane Entertainment, in which she performed opposite Brandon Iron. She entered the industry under the name "Mirage", but began calling herself "Briana Banks" in 2000, after having the first of two breast enlargement operations. Her first appearance as 'Briana' was in the film Decadent Whores 9. She appeared in Penthouse magazine as Pet of the Month in June 2001. The same year, she signed with Vivid Entertainment.
Banks claims to have the longest legs in the business (36" inseam), and is known for having large breasts on a thin body. She has a ribbon tattoo on her lower back. For several years, her regular boyfriend was pornographic actor Bobby Vitale, but they broke up by 2006.
In 2002 Banks was one of the first pornographic actresses to have an action figure made in her likeness, by Los Angeles based company Cyber F/X and Sota Toys.
Banks was a contributing author in the 2004 book How To Have a XXX Sex Life: The Ultimate Vivid Guide (ISBN 9780060581480, from ReganBooks). In the book she and other Vivid contract stars give advice and tips about sex, as well as relate anecdotes from their personal sex-lives.
On 13 October 2006, WTAE-TV News in Pittsburgh, PA reported that Banks, called "a local porn star", was filing a federal lawsuit seeking more than US$75,000 in damages against Doc Johnson Enterprises, a sex toy manufacturer, claiming the company violated an agreement to make molds of her genitals, making 10 unauthorized products from those reproductions while the agreement was that the company would only make two.