Patterson was raised as an only child by her mother in Los Angeles, California, where she was born. Her name is her mother's middle name: Marnette. Her aunt is Dana Dillaway, former child Actress who appeared in Giant (1956) as Elizabeth Taylor's and Rock Hudson's daughter Judy (age 4). In 1989, Patterson was the junior vocalist winner on Star Search.
Patterson also starred in the short-lived WB sitcom Movie Stars and the made-for-TV movie The Stalking of Laurie Show. She has appeared in films such as Camp Nowhere (1994), Patterson made appearance in That '70s Show as Shelly in the episode: "Eric's Panties" in 2000. Who's Your Daddy? (2003), Pope Dreams (2005), and Cloud 9 (2005). She also voiced Lucy van Pelt in It's Christmastime Again, Charlie Brown and It's Spring Training, Charlie Brown. In 2004, Patterson appeared on Grounded For Life as an underage drinker. In 2005, she guest starred on Supernatural as a young high school student, Charlie, in the episode Bloody Mary.
In 1996, Patterson appeared briefly as a volleyball schoolgirl attracting the attentions of Tommy in the premiere episode of 3rd Rock From The Sun.
In 2006, Patterson landed the role of Christy Jenkins on Charmed, a witch kidnapped from her home by Scabber Demons at the age of seven. These demons held her captive within The Underworld for fifteen years and intend to use her as the key to the "ultimate power" under the orders of The Triad, a trio of powerful upper-level demons who had originally sent the demon mercenary Belthazor/Cole Turner undercover to defeat The Charmed Ones. Her character could mentally cause objects and beings to burst into flames. She appeared on Charmed for eight episodes.
Patterson also portrayed Holly Little in the 2008 film Starship Troopers 3: Marauder. She starred as Maggie Schaffer on the web series, called LG15: The Resistance. In 2009, she appeared on an episode of the TV series House, where she starred as Ashley. In 2011, she appeared briefly on an episode of The Mentalist ("Every Rose Has Its Thorn") as a con Artist who would sleep with wealthy men and then blackmail them. Her character was named Naomi/Victoria. Patterson is close friends with Jennifer Finnigan, her co-star on The Stalking of Laurie Show.
On September 4, 2011, she married James "Jimmy" Verzino, an advertising executive, at a ranch in Malibu, California.
