"Gokujō!! Mecha Mote Iinchō" centers around Mimi Kitagami, a cheerful and diligent middle school student who serves as the class representative. Mimi is known for her strong sense of responsibility and her desire to help others, often going out of her way to solve problems for her classmates. Her life takes an unexpected turn when she encounters a magical creature named Shippo, who grants her the ability to transform into a "Mecha Mote" version of herself. This transformation enhances her charm and confidence, allowing her to tackle challenges with newfound determination.

The series explores Mimi's daily life as she balances her responsibilities as class rep with her personal growth and relationships. Each episode typically presents a new problem or conflict, often involving her classmates or school-related issues. Mimi uses her Mecha Mote abilities to inspire and support those around her, fostering teamwork and understanding. Her transformations are accompanied by a catchy musical sequence, emphasizing her role as a positive influence in her school community.

Key characters include Mimi's classmates, such as Serinuma Kippei, a laid-back and carefree boy who often provides comic relief, and Kujō Karen, a sophisticated and intelligent girl who occasionally clashes with Mimi but ultimately respects her dedication. Shippo, the magical creature, serves as both a guide and a source of humor, often offering quirky advice or commentary on Mimi's actions.

The narrative emphasizes themes of friendship, perseverance, and self-improvement, with Mimi's journey serving as a vehicle to explore these ideas. While the series incorporates fantastical elements through the Mecha Mote transformations, it remains grounded in the everyday struggles and triumphs of middle school life. The episodic structure allows for a variety of scenarios, from resolving misunderstandings between classmates to organizing school events, all while highlighting Mimi's growth as a leader and individual.