Chiaki Matsushita is a supporting first-year student in Classroom of the Elite. She is usually shown as a calm, observant girl who hides how capable she really is, and she appears in the story as a student who can quietly notice things others miss.

Her classmates

In the school year shown in the series, Matsushita is in the same class as other first-year students at Kōdo Ikusei, and she is commonly associated with Class 1-D / later Class 1-C to 1-D reassignment depending on the stage being described. Her classmates include well-known names such as Kiyotaka Ayanokōji, Kei Karuizawa, Suzune Horikita, Kikyou Kushida, and Satoru Kaneda, among others in the same first-year group.

Who she is

Matsushita is not one of the loudest characters in the series, but she is often described as more perceptive than she first looks. Some fan discussions and character pages describe her as someone who keeps a low profile while still being intelligent and analytical.

Quick context

If you mean “which class is she in with who,” the short answer is that she is part of Ayanokōji’s first-year class group, alongside the main Class D classmates like Horikita, Kushida, Karuizawa, and others.

TL;DR: Matsushita is Chiaki Matsushita, a supporting student in Classroom of the Elite who sits in the same first-year class as Ayanokōji, Horikita, Kushida, Karuizawa, and the rest of their class.