Clemont is a young boy who serves as the Gym Leader of Lumiose City in the Kalos region and is one of the main traveling companions of Ash Ketchum throughout the Pokémon XY and XYZ anime series. He is joined on his journey by his energetic and outspoken younger sister, Bonnie. Clemont is characterized by his bright yellow, messy hair with a distinctive lightning-bolt shaped tuft at the top, large round glasses, and a blue jumpsuit. He almost always carries a large backpack of his own design, which contains a variety of his inventions and features a robotic arm he calls the Aipom Arm.

His most defining trait is his passion for science and invention. Clemont is a self-proclaimed genius inventor who is constantly creating new gadgets to solve problems or assist his friends. However, a persistent running joke is that his inventions, which he often names with the prefix Clemontic, almost inevitably malfunction, short-circuit, and explode shortly after being activated. Despite these frequent failures, his enthusiasm for technology and his belief in scientific solutions never wavers. He is dedicated to logic and can become flustered or fearful when confronted with phenomena that seem to defy rational explanation. Apart from his inventing, Clemont is a capable battler and a knowledgeable Pokémon Trainer, skills he has developed as a Gym Leader.

Clemont's role in the story is initially complex. When he first meets Ash, he does not reveal his identity as the Lumiose City Gym Leader. Instead, he, along with Bonnie, decides to travel with Ash and their friend Serena. The reason for this secrecy is that Clemont created a robotic substitute named Clembot to manage the Gym in his absence, but the robot malfunctioned and ejected him, preventing his return. After reclaiming control of his Gym with Ash's help, Clemont entrusts the Gym to a reprogrammed Clembot and continues his journey, motivated by a desire to grow stronger and learn from Ash. His personal journey becomes one of self-improvement, as he seeks to become a Gym Leader worthy of challenging strong Trainers. This culminates in a formal Gym Battle against Ash, which serves as a major milestone in his development.

Clemont's relationships are central to his character. His bond with his younger sister Bonnie is a driving force in his life. He is extremely responsible, protective, and caring toward her, often acting as a parental figure. He frequently scolds her for wandering off but is always affectionate and deeply concerned for her safety. Clemont also forms a strong rivalry and friendship with Ash. He respects Ash's determination and battling style, often using him as a benchmark for his own growth. Serena is another close traveling companion, and the group shares a strong familial dynamic.

His development is closely tied to his Pokémon. His loyal Bunnelby is his first seen partner, known for its digging skills. He later catches a playful and food-loving Chespin, who often causes mischief. One of his most significant story arcs involves reuniting with a Luxio, who was once a Shinx he befriended as a child. After mending their broken trust, Luxio evolves into a powerful Luxray, symbolizing Clemont's own maturation and his ability to confront his past mistakes. This evolution, along with his intense training before facing Ash, highlights his growth from a well-meaning but insecure inventor into a more confident and capable individual.

Clemont possesses several notable abilities. As a Gym Leader specializing in Electric-type Pokémon, he has a deep strategic understanding of battles. He is a skilled programmer, having designed both the Kalos Power Plant's systems and the Clembot. His most prominent tools are his Clemontic Gear inventions, which range from airbag backpacks to various battle aids and everyday gadgets. While their effectiveness is unreliable, his creativity and technical knowledge are undeniable, making him a unique and memorable member of the Kalos traveling group.