During her first job modeling, King was turned onto heroin and had an addiction to the drug from age fourteen to nineteen. In 1997, her boyfriend, twenty one year old fashion photographer Davide Sorrenti, had died from what was thought be a kidney ailment brought on by excessive heroin use. Following his death, King became sober, and went to rehabilitation at age nineteen for her addictions to both heroin and alcohol. In 2006, she commented that her past reputation as a "party girl" is "like another lifetime" and she now thinks of herself as a different person.

In September 2000, King dated Kid Rock and the couple made an appearance on The Howard Stern Show. In January 2005, while working on the set of Fanboys, she met husband Kyle Newman, the film's director. Within three months of dating, the two moved in together. Newman proposed in Spring 2007, and the two married on November 23, 2007 in an "intimate and relaxed" ceremony in Los Angeles at Greystone Park and Manor, where