Dexter is the main character and protagonist of Dexter's Laboratory. He is a boy genius who has a secret laboratory. His intelligence makes him the brains of the family and he is one of the world's greatest inventors, having created countless weird and amazing machines and experiments. He is always working on new inventions and creations every day, but his sister Dee Dee is always breaking into his lab and destroying his work. The daily events surrounding Dexter's life mainly revolve around his relationship with his sister and everything that happens between the two.

Dexter is a very short young boy who has curly red hair that was passed down to him from his mother He wears a pair of glasses that appear semi-circular at normal times, but when he widens his eyes, the tops of them round out. He wears a little white lab coat with black buttons on it. He also wears purple gloves, and a pair of black rubber zipper boots. Occasionally he may or may not wear a pair of black pants that match his boots. He speaks with a Russian accent despite the rest of his family not having any accents.