She was named after a character in a Jacqueline Susann book called Once is Not Enough, featuring a character named January Wayne.

According to her interview in GQ Magazine, she desperately wanted to leave South Dakota by the age of 16. She was spotted by a modelling scout while she was out shopping and he wanted her to work in New York.
However she was sensible and finished school first, waiting to turn 18 before she made her big move.

At 18 years old, she moved to New York where she began modelling. One of the biggest modelling jobs she won was for Abercrombie & Fitch.

She also lived in Paris for a little while. She spoke about her time in Paris in 'Interview Magazine' saying: "That’s when I got into my introspective, moody period, writing in my journal and going to visit Jim Morrison’s grave".

January later moved to Los Angeles, where she then decided to go into acting. Her acting debut occured with a small role in the independent film "All the Rage" (1999), starring Jeff Daniels and Anna Paquin.

She also won a role in the suspense thriller The Glass House (2001). Since then, she played supporting roles in Bandits (2001), Full Frontal (2002), and Anger Management. She was also cast in American Wedding, the 2003 third installment in the American Pie series, as the sister of Michelle (played by Alyson Hannigan).

In her private life, January has been romantically linked with two major comic actors, Jim Carrey and Ashton Kutcher.

She has worked with some huge hollywood actors, including Jack Nicholson, Adam Sandler, Elisha Cuthbert, Tommy Lee Jones and Seann William Scott.