January Jones was born on January 5, 1978 in Sioux Falls, South Dakota. She is the daughter of Karen Sue (née Cox), a sporting goods store manager, and Marvin Roger Jones, a gym teacher and fitness director. She is of Czech, Danish, English, Welsh, and German ancestry. She was named after the character January Wayne in Jacqueline Susann's potboiler novel turned film, Once Is Not Enough (1975). She has two sisters, Jacey Jones and Jina Jones].

Her family moved to the small town of Hecla, South Dakota, with a population of just some 400 souls in 1979, when she was one year old; they moved back to Sioux Falls in 1986. After graduating from Roosevelt High School, she moved to New York City to become a model. Despite her stature (5'6", which is short for a fashion model), she got modeling gigs, including Abercrombie & Fitch ads. However, modeling was just a means to an end, to get out of South Dakota and avoid going to college.

She got her first taste of acting from TV commercials and found that she had flair for it, even though she did not act in high school and had no training. January appeared in a couple of television pilots and a cable television series before making her big screen debut in All the Rage (1999), an indie that never got a real release. She followed it up with a small role in the teen thriller The Glass House (2001). Her actual debut in the sense of attracting attention was in the near silent role of the beauty who entices Jane Fonda's son, Troy Garity, in the Bruce Willis-Cate Blanchett-Billy Bob Thornton comedy Bandits (2001). It was not a career-making part. At the time the movie was released, she was ending a three-year relationship with Ashton Kutcher.

Small roles followed, including a "don't blink or you won't see me" part in the Adam Sandler-Jack Nicholson comedy Anger Management (2003). She gained some career traction with a good role in another comedy, American Wedding (2003), a sequel to American Pie (1999). Until she landed the part on Mad Men (2007), which made its debut on AMC in 2007, her career was steady but undistinguished. "I choose roles that are not me", January has said. The role of Betty Draper has garnered her two Golden Globe nominations and an Emmy nomination as Best Actress. Her cool, Grace Kelly-ish blonde ice queen looks -- counterpointed by her soul burning in her bright blue eyes -- have established her as a retro icon of the 21st Century.