For the first few seasons of Michael Scott's (Steve Carell) unconventional management style but she surprisingly entered a romantic relationship with her employee.
Throughout season 1 and 2 of The Office, Jan viewed Michael as the inept boss of the Dunder Mifflin Scranton branch. She constantly had to force him to do his job such as picking the employee healthcare plan and laying off one of the workers at the branch. Later in The Office season 2, Jan finally viewed Michael in a different light after he managed to acquire a big client by using his odd tactics. She then had a one-night stand with Michael but wouldn't commit to a relationship. Jan and Michael didn't officially become a couple until their hookup went public following their trip together to Jamaica.
By the end of The Office season 3, Jan was fired from Dunder Mifflin so she moved in with Michael at the start of the following season. Her spending habits and unemployment start to annoy Michael but the tension doesn't boil over until the episode, "Dinner Party." The couple got into a major fight resulting in Jan throwing a Dundie Award into Michael's flatscreen TV. They then break up for good but that's not the end of Jan. Following the breakup, she kept at it with her candle-making company, Serenity by Jan. Jan also decided to have a baby by using a local sperm bank. The unknown father of her daughter, Astrid, could have possibly been Kevin according to a deleted scene.
When Jan returned to The Office in season 7, it was revealed that she was the director of office purchasing for the Scranton area hospital. She also made a brief appearance in Threat Level Midnight, Michael's homemade movie from years prior. Hardin reprised her role again in The Office's ninth and final season. By then, Jan was the CEO of the Scranton White Pages. She wanted to get revenge on David Wallace by proving how successful she became after being fired from Dunder Mifflin. After a meeting with Dwight, Pam, and Clark, Jan reluctantly gave Dunder Mifflin her business but that didn't last long. Jan backed out of the contract after Andy took away the discount that Dwight offered.
According to NBC's follow-up on characters from The Office, Jan remained at the Scranton White Pages. She also had dreams of becoming a stage mom as she tried to get Astrid on a season of Toddlers and Tiaras. In addition, Jan struggled to find a therapist that would treat her, most likely due to her demanding demeanor. Thankfully, Jan and Michael moved on from one another and found happiness elsewhere because that relationship was always heading for disaster.