Poppy Playtime is the titular character and main deuteragonist of Poppy Playtime. The Player first encountered her at the end of Chapter 1: A Tight Squeeze. Her product is the first known to be produced by Playtime Co..

Poppy is a small, porcelain doll with white skin. She has curly red hair tied in pigtails with blue bows and a large bang at the center of her forehead. Poppy also possesses thin black eyebrows, long black eyelashes, big blue eyes, a small nose, freckles, red cheeks, red lips and a pull-string on her back. After the Train crash, she has a small crack on her right cheek. Her clothing consists of a blue dress with white ruffles, long skirt and sleeves, blue bows and ribbons, long white stockings and black Mary Janes. Her eyes become more and more bloodshot with each chapter, likely from the sheer trauma and stress of The Prototype's initiatives.

From Chapter 3, onwards, Poppy’s model is altered, with her hair becoming longer and more detailed, receiving more freckles and improved detail on her dress, most likely due to the shift in game engines, with Poppy Playtime transitioning from Unreal Engine 4 to Unreal Engine 5.

In Chapter 5, her blue dress is completely shredded, revealing the white underdress, and her arms were wrapped in bandages. Her eyes are no longer bloodshot. The Prototype later squeezes her head in his claw, resulting in the porcelain of her face cracking all over, as well as losing her right eye and a large amount of her hair. Her voice also noticeably becomes more tinny after this.

In her commercial, Poppy is portrayed as a social, outgoing, dainty, and elegant individual. She cares a lot about her appearance and always wants to look her best, as demonstrated by the Vintage Poppy Commercial. Poppy is also very courteous, politely asking her owner if they could polish her shoes and brush her hair.

As a living doll, although she still retains her general personality, Poppy behaves differently to her commercialized persona. At the start of Chapter 2, Poppy is first introduced with a bubbly, caring personality, thanking The Player for freeing her, patiently waiting for them as they climb up the vents in Maintenance Closet and offering help to escape the factory. Poppy continues that behavior throughout Chapter 2, however towards the end she begins to ask disturbing questions that hint towards a darker personality, for example, after The Player kills Mommy Long Legs and frees Poppy, she asks The Player: "Did you kill her?".

Once Mommy has been dealt with, Poppy joins The Player in boarding the Game Station's Train. After entering the Train Code and starting the Train, Poppy commends The Player for following her wishes and being capable of doing whatever she asks. The train derails, preventing any escape. In Chapter 3, it is revealed that Poppy is seeking revenge on The Prototype for the torment that she and others suffered at his hands, fearing that he would kill them if they tried to leave. She seems to have connections with Kissy Missy, as she was able to persuade her to cease attacking The Player, and showing significant distress when Missy was attacked offscreen at the conclusion of the chapter. In Chapter 4, she has been shown to be intelligent as Doey the Doughman said that Poppy told them what to do, where to go and how to do it, and it all made sense. Later, Doey proclaims, that Poppy is selfish and that she only cares about herself and her own goals, due to her obsession with her main goal to get personal revenge on The Prototype. After the Safe Haven's destruction, Doey also accused her and The Player in ruining everything. In Chapter 5, Giblet was also taken aback after learning her ill-fated plan to destroy the factory's foundations in order to eliminate the Prototype. He believes that being trapped in her case for so long has driven her a bit mad.