Sadie is an OB/GYN, and a close friend of Jessica Day. She is a lesbian, and has been married for over five years to Melissa. Sadie was nine months pregnant with their first child at the end of season two.
Sadie is first introduced as one of Jess's friends while they gossip, with Cece, about Nick's new girlfriend, Julia, in the loft kitchen. Julia is indirectly offending Jess because she thinks she comes off too girly for an adult, and is being condescending and judgmental about it. Sadie can't believe that Julia doesn't like desserts, but she admits that the first time she met Jess, she was taken aback by her bright pink ribbon hat. Nick walks in and Cece tells him that she thinks Julia is a bitch, but he doesn't understand what the problem is, because Jess admits that Julia never explicitly admitted she disliked her. Nick says that he likes Julia because she doesn't play any games, but Jess disagrees and points out, surprisingly, that she asked her if Nick was sleeping with other people. When Sadie remarks that Julia's girl games are classic moves even in the lesbian community, Cece is practically bowled over when Schmidt rushes out of his bedroom at the mere mention of the phrase.
"Did you just hear the words 'lesbian community' and come running out of your room?" Sadie asks him, and without skipping a beat he admits that's exactly what's happened. Schmidt asks Sadie if the women in the community of which he speaks look more like Cece, or a little more like Nick. Sadie stares at Nick and admits she did once date a woman who looked a lot like him, named Felicia.
Schmidt has left his towel in his room with his dehumidifier to keep it dry, but after his shower he realizes he has to cross the apartment naked while Jess sits in the living room, knitting with Cece and Sadie. He deplores them not to look, but is dismayed when he realizes they're not actually looking. Still dripping wet, he slips on the wood floors, dropping the brown hand towel and finally getting a look out of the women. Sadie points her knitting needle in his direction and laughs. "See, he's a natural blond!" she cracks. He launches into a rant about the lack of sex he's been having since Jess moved in, the exact opposite of what he assumed would happen when he got a girl roommate. Instead, he's stuck with a friend, in Sadie, who "samples from the gumbo pot," and Cece, on whom he swears he will never give up. Sadie likes dirty jokes and Schmidt suggests that the two of them get together some time to discuss "O.S.I." - "our shared interest." Jess orders Schmidt to clothe himself, just as Julia shows up at the door.
She's come to apologize to Jess for being rude to her, and is hoping they can be friends as her relationship with Nick grows stronger. Jess accepts the olive branch and invites her in to join the women for their crochet night. Julia opens up to the women about her tough high school years, and they all amiably relate to how brutal girls can be to one another. When Nick gets home, he's surprised and happy to see the women getting along with one another.
During a game of football with some guy friends, including Schmidt and Winston, Nick is tackled by Jess. He falls to the grassy field in agonizing pain, and Jess is the only one who offers to help him, even though Jess is the last person whose help he thinks he needs. She takes him to see Sadie at her gynecologist's office, since he has no health insurance and cannot go see a regular doctor. She agrees to fit him in between her pregnant patients, much to Nick's discomfort because he both hates doctors and points out, unable to sit up straight due to the pain in his spine, that he doesn't have a vagina.
Nick waits with Jess in the exam room, lying face down in the chair because it's the only way his back won't hurt, when Sadie walks in. She and Jess share a friendly hug as she and Nick are reacquainted. As Jess explains how he got hurt, Sadie is surprised that Jess managed to hurt him, slyly adding insult to injury. She examines his back, then "does not" tell him officially that he bruised his spine, she "does not" give him medication for women's menstrual cramps to ease the pain, and she "does not" urge him to take them as she gives him the pills with a small cup of water. Nick gets confused, with Jess encouraging him to take the pills seemingly in conflict with doctor's orders, but he swallows them anyway, and when he does Sadie remarks, on the record, that the pills should do the trick to ease his "baby back-ache." (Later, he admits to his friends that the pills make him feel warm in his uterus.)
As he gulps the pills back with the water, Sadie notices a growth in his thyroid when he swallows, and arranges for an ultrasound at a colleague's office the next day. Nick doesn't want to bother with the test, but Sadie tells him that he doesn't have a choice. On her way out of the exam room, she calls after Jess to make sure he goes for the appointment.
For the next 24 hours, the entire gang is scared that Nick has cancer and is going to die, but the tests come back negative.
Sadie and her wife, Melissa, are having dinner at the loft with Jess, Cece and Nick, to celebrate their five-year anniversary. Sadie is reflecting on the joy of commitment when she's interrupted by Schmidt, playing loud sex games in his bedroom with his company's VP. Jess offers Cece a glass of six-dollar wine, but Sadie declines, revealing to the group that she is pregnant. Leaving his boss in his room, Schmidt emerges for just a few seconds to congratulate the women on their "lesbian baby." Later, Schmidt asks Sadie for advice on female pleasure from her unique perspective as a lesbian gynecologist, so she tells him to book an appointment at her office after proudly admitting that she "know(s) my way around a Grizzly Adams." For the comment, Jess tries to get her to put money in the "Douchebag Jar."
Sadie feels especially lucky to be pregnant, letting Jess know that once a woman hits 30, her fertility declines sharply. This scares Jess, who's 31 and not ready for kids, but knows she wants them eventually. Cece, on the other hand, is less enthusiastic about kids and assumes she's got all the time in the world to find the right guy and settle down. Reluctantly, Cece goes with Jess to take a fertility test at Sadie's office.
Later that week, Schmidt has booked his appointment, and promptly shows up at Sadie's OB-GYN practice for their discussion. She begins by showing him illustrations of the female anatomy, but it quickly becomes clear that Schmidt has more than just an idea what to do in the bedroom. Sadie finds herself turned on by their sexually driven conversation, admitting weakly, "It's the baby hormones. They are not as gay as me." She confirms for him that he is, in fact, a "vagenius."
Jess' fertility results turn out great, but Cece's egg count is low. Sadie tells Cece if she wants kids, she has to start having them now. This ultimately prompts Cece to agree to an arranged marriage with Shivrang.
Although neither woman is shown on camera, the first of three holiday parties that the gang attends on the Saturday before Christmas is a cookie-decorating party at Sadie and Melissa's condo. It is notably packed with lesbian women, which forces Schmidt to call it a "party black hole." However, Dr. Sam Sweeney is one of Sadie's colleagues, and has shown up purely to see his ex, Jess, who he knew would be there because she accepted on Facebook.
Sadie comes to Cece's surprise bachelorette party, hosted by Jess at the loft. She is 39 weeks pregnant, wearing a pink zebra print bra over her maternity dress, and awed by the number of beautiful models at the party. She gets nervous around them and starts acting weird, so Jess threatens to call her wife if she starts acting out. When Cece arrives with Shivrang's conservative aunt, she's surprised to see Cece and Sadie leading the chant to play "Pin the Dong on the Shivrang." Cece reveals to her friends that she's never seen Shivrang's penis, which surprises all of them. Sadie remarks suggestively, pointing at the target on a life-size cutout of Shivrang, that she still knows where it goes, still urging her to play the game.
With Ankita G still in the washroom, Jess is trying to make Cece feel better, while Sadie and the models are less supportive. "What if it's shaped like a carrot?" wonders Sadie. "What if it's curly?"
All of the women are bored by the unexpectedly G-rated bachelorette party, and Sadie has taken to discreetly smelling the models that sit next to her on the loft's large sofa. She suggests that Jess show the photo slideshow that Jess made for Cece, and the models egg her on, but the photos are all explicit and horribly embarass her.
Jess asks Nick to get a picture of Shivrang's penis to show Cece before the wedding, but winds up taking a picture of his own penis, which Winston then sends pretending it's Shivrang's. When Jess receives the text, Sadie and the women crowd around her, inciting Ankita G's interest. She reveals that where she comes from, women cry for days over the fear of marriage to complete strangers. For the rest of the night, Ankita shares her stories with the girls, who listen intently before Sadie falls asleep on the couch. She's awakened by the models cheers when Nick, Winston, and Shivrang return from Clyde's Bar, and a talk with Sadie nearly results in him dropping his pants to show her his penis and get past the issue. Cece encourages him not to, but they make amends anyway.
- She is presumably in her late 30s or early 40s, based on her admission in "Eggs" that she was running out of time to have a baby. Her exact age has not been revealed.
- When Jess and Sadie met, Sadie was slightly taken aback because Jess was wearing her bright pink ribbon hat.
- Once dated a woman who looked a lot like Nick, named Felicia. Jess has also met Felicia, and concurs that she looked like Nick. ("Jess & Julia")
- Likes dirty jokes and discussing the female anatomy, which she and Schmidt quickly realize they have in common. Sex with women is in fact their "O.S.I." - "our shared interest" - as pointed out by Schmidt.
- Celebrated her five-year wedding anniversary in November 2012. ("Eggs")
- She did not attend Cece's wedding at the end of season two despite their close friendship, presumably because she was due to give birth around the same time.
- (To Schmidt): "I know my way around a Grizzly Adams."
- (To Schmidt): "It's the baby hormones. They're not as gay as me."