Richards was born in Downers Grove, Illinois, a suburb of Chicago, to Irving Richards (who used to work for a phone company) and Joni, who owns a chain of coffeehouses named "Jitters"; she is of Welsh descent on her father's side and of Croatian descent on her mother's, and was raised a Catholic.

Richards moved to California with her family during her teen years, and graduated from El Camino High School, where she was a cheerleader, in Oceanside, California.

Richards spent the majority of the 1990s appearing in television movies and lower-budget films. Her first starring role in a wide theatrical release was (1999), which had a high box office gross and contributed to Richards' reknown. In addition to her film work, Richards has made regular appearances in the situation comedies .

Throughout the early 2000s, Richards appeared in several film roles which both parodied and utilized her image as a sex symbol, including

Richard has dated actor Patrick Muldoon. She married actor Charlie Sheen in 2002. They had two daughters: Sam J, who was born on March 9, 2004, and Lola Rose, who was born on June 1, 2005. In March 2005, Richards filed for divorce. The couple briefly reconciled and were seeking marriage counseling to mend their relationship. However, on January 4, 2006, Richards' representative announced that she was continuing with the divorce.

Richards enjoys kickboxing.