Penny is a former waitress, actress and a current pharmaceutical sales rep. Originally from Omaha, Penny moved to California with dreams of becoming a Hollywood actress. Since 2007, Penny has lived in the apartment across the hall from Sheldon and Leonard, who is now her fiance.
Penny's lack of education sets her apart from the guys and Amy and Bernadette, though she has street smarts which many of the others lack. Penny has also proved to be very handy as a result of growing up on a farm, where she rebuilt a tractor engine at the age of twelve. Penny has been called on by the guys to defeat spiders and online hackers. In 2012, Penny went back to school for some history and psychology classes, although she initially kept it quiet from Leonard who she felt would make a big deal about it.
Penny has usually had little interest in the guy's geeky hobbies, though she has tried to get on board with some of them for the sake of her relationship with Leonard. In some instances, Penny has shown an interest in their activities, once even becoming addicted to online gaming.
During Penny's time as an actress, she was often short of money and came to rely on the guys. Penny had a habit of eating their food without contributing and of freeloading on their WiFi, leading Sheldon to repeatedly change the password. The guys were once called on to retrieve money owed to Penny by her ex-boyfriend Kurt. After Penny received a royalty check from her commercial, she paid Sheldon and Leonard back by buying them mint edition Spock collectibles.
Not much is known at Penny's family, not even their last name. Her father, Wyatt, visited Pasadena once while Penny and Leonard were broken up. Penny pretended to still be dating Leonard, whom Wyatt approved off, in a bid to keep him off her back about her otherwise bad dating choices. Penny has a brother who is a chemist of sorts (in a meth lab) and who may currently be on the run in Mexico.
Relationship with Leonard
From the moment he first saw Penny, Leonard was smitten with her. It took almost a year of Leonard pining over Penny before he finally asked her out, an offer which Penny accepted. After an "okay" date, Penny broke things off with Leonard as she was afraid she wasn't smart enough for him. The pair then started seeing other people again.
Penny's feelings for Leonard became clear when Leonard and the guys went on a three month expedition to the arctic. Before Leonard went on the expedition, Penny couldn't work up the courage to not tell him to go. When the guys returned from the Arctic, Penny kissed Leonard and they then started a relationship.
When Leonard prematurely told Penny he loved her, she broke things off as she wasn't in the same place he was. Following their break-up, despite things being awkward between them at first, Leonard and Penny worked to make sure they could still be friends. While they both dated other people, Leonard started a serious relationship with Priya, Raj's sister. Leonard and Priya's relationship was difficult to watch for Penny, who clearly still harbored feelings for Leonard, especially when Priya demanded Leonard no longer be friends with her.
When Priya moved back to India, her long-distance relationship with Leonard fell apart. Soon, Leonard took the bold move of asking Penny out to dinner on a date, an invitation Penny accepted. Following a beta test period of their relationship, Penny and Leonard got back together and have been in a relationship ever since. For a long time, Penny was unable to say "I love you" to Leonard, but finally told him when Leonard was worried about losing her to another guy.
Following a setback in her acting career, Penny proposed to Leonard in a drunken state. Leonard, realizing Penny wasn't in the best frame of mind, hesistated, much to Penny's initial anger. Although Leonard was worried it would end their relationship, Penny assured him they were still together. When Penny's acting career took another hit as she was fired from a low-budget movie, she vowed to start making better decisions. She proposed to Leonard, who wondered whether he career troubles were the only reason she wanted to get married. After Penny convinced Leonard that wasn't the case, he proposed to her and she accepted.
Apart from Leonard, Penny has only really had two other somewhat serious relationships that we know about. Penny moved in to her apartment following her break-up with Kurt, her hulking boyfriend. Penny asked Leonard and Sheldon to go get some of her stuff back from Kurt's apartment, leading them to get "pantsed". Leonard and Kurt would have other run-ins at Penny's Halloween party and when Kurt owed Penny money.
Penny's other serious relationship, eventually revealed to be more serious than either of them realized, was with Zack Johnson. Following her break-up with Leonard, Penny started dating Zack, a dim-witted guy who delivered the menus to the Cheesecake Factory. Following a one-night stand with Zack, Penny blamed Leonard for ruining her for dumb guys. She and Zack later got back together, though it's not clear when they broke up. At Thanksgiving 2013, after Penny mentioned a "fake Vegas wedding" she and Zack had, Penny learned that she was married to Zack. Leonard helped Penny sort out the paperwork to have the marriage annulled.
Penny has a complicated friendship with Sheldon, who is very much her polar opposite. Though Penny is often the subject of Sheldon's derision, she has a soft spot for him and has often been like a big sister to him. Penny has cared for Sheldon when he was sick, let him stay in her apartment when he was locked out of his, taken him to Disneyland, and run all manner of errands for him. In return, Sheldon has lent Penny money when she was hard up and has cared for her when she dislocated her shoulder. Still, it's not all fun and games, especially for Penny, as Sheldon has tried to train her with chocolate, teach her as if she was a gorilla, and has even banished her from the apartment for breaking his rules.
Penny has had an uncomfortable friendship with Howard, who for three years tried in vain to pick up her. Penny found Howard's advances disgusting, though over time she did start to feel compassion for the guy underneath the "creepy candy coating". Since Howard settled down with Bernadette, Penny is much more comfortable around Howard and has occasionally been surprised by how mature he is now.
From the beginning, Penny cared for Raj, even though he could not talk to her. In the early days, Penny sometimes had to leave the room so Raj could speak. When Raj and Penny spent an evening drinking together, drowning their own respective sorrows over Leonard and Priya's relationship, they inadvertently spent the night together. Penny feared she had ruined her friendship with Raj and her relationship with Leonard. Her concerns were allayed when Raj admitted they didn't actually have sex.
When Penny accompanied the guys to the comic book store, she met Stuart, who made a drawing of her and asked her out on a date. Stuart and Penny went on two dates, but their relationship ended when Penny accidentally said Leonard's name as they made out.
After Amy began dating Sheldon, she joined Penny and Bernadette for girls' night. Since then, Amy has made herself part of Penny's social network, and considers her and Penny "besties". Penny has helped Amy overcome some of her awkwardness and Amy is thankful to Penny for giving her the social life she always craved.
Penny met Bernadette when they both worked at the Cheesecake Factory together. When Howard called on a deal he had with Leonard, Penny set Howard up with Bernadette. As Howard and Bernadette started dating, Bernadette became a part of the group and began spending more time with Penny and later Amy.
Penny worked as a waitress at the Cheesecake Factory while she waited for her acting career to take off. Penny was already working at the Cheesecake Factory when she met Sheldon and Leonard and, as a result, the guys began to eat at the restaurant on Tuesday nights. Penny quit her job at the Cheesecake Factory in 2014 to focus on her acting career.
Penny moved to California to make it as an actress in Hollywood, though she struggled to break through and has only had a few paying jobs. After meeting Sheldon and Leonard, her first acting gig was in a one night showcase production of Rent, which Leonard and Sheldon avoided through a convoluted lie. She later starred in a production of The Diary of Anne Frank above a bowling alley, and had a part in a nationwide commercial for hemmorhoid cream.
Following a stage production of A Streetcar Named Desire, where Penny's performance even impressed Sheldon, Penny's big break was supposed to be a bit part on the CBS drama series NCIS. Penny was disappointed that her part on the show was cut, and she decided that to make it as an actress she should quit her job at the Cheesecake Factory and focus on acting full time.
Before Penny met the guys, she had a role in a low budget horror movie Serial Ape-ist. Though she didn't learn the guys knew until 2013, Howard reportedly found the movie on the Internet the same day they met Penny. Penny was offered a part in the sequel to the film, "Serial Ape-ist II: Monkey See, Monkey Kill", and initially turned it down. When the part became available again, Penny reluctantly took the job. After Penny was fired from the movie, she decided to take a break from acting, realizing she didn't need a Hollywood career to be happy.
When Penny was without a job, having quit her waitressing job at the Cheesecake Factory and given up on her acting career, Bernadette got her an interview at her pharmaceutical company, Zangen. During her job interview, Penny was worried she wasn't up for the job and made a bad impression with the interviewer. After Penny and the interviewer bonded over their mutual fear of Bernadette, Penny got the job. Penny has taken the job seriously since, even blowing off a night of Vegas fun so she could study up on her work material.
Sheldon: There are post-prom mating rituals?
Penny: Not always. Unless your date drives a van with an air mattress, then always.
Raj: (To Amy) If you were having Sheldon's baby, would you really want him in the room?
Penny: If he's in the room when they're making the baby, I'll give you $10.
Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your ken can kiss my barbie.
Leonard: If I take it off, Sheldon wins.
Penny: Sweetie, every night you don't kill him in his sleep, he wins.
(Sheldon knocks on Penny's door three times)
Penny: Who do we love?
Sheldon: Penny. (Knocks 3 times)
Penny: Who do we love?
Sheldon: Penny. (Knocks 3 times)
Penny: Who do we love?