Sayori is initially portrayed as the character archetype of a Genki Girl, expressing a bubbly and cheery disposition. She is very clumsy, noted for finding ways to accidentally hurt herself or to drop random things. Regardless, she is shown to be a jokingly cunning individual who can trick others to get food, shown after managing to eat Natsuki's cookie without her permission. Sayori has also been known by the protagonist to obsess over activities that she loses interest in later. She states that writing poetry and studying literature is different to her than those other interests because it helps her explore her feelings.

However, it is later revealed that she suffers from bad depression and works so hard to make the people around her happy to cope with her own lack of self-love amongst other things. She is also usually the only character, other than the protagonist, shown to break up arguments, Monika noting that her sentiments are necessary to keep a relaxing atmosphere in the Literature Club. This is proven by her absence in Act 2. Monika notes that while she may look like a good leader, Sayori is usually better when it comes to dealing with people, notably at mediations. She tries her best to help everyone be happy and dislikes attention directed at her well-being because she feels unworthy of anything that others have to offer her.

First two lines are from the source material, the last line is from a previous video I made.