Brock is a fictional character from the Pokémon anime, known for his role as the former Gym Leader of Pewter City, where he specialized in Rock-type Pokémon. He is the eldest of ten children, a responsibility that initially kept him bound to his family's home. After being defeated by the aspiring trainer Ash Ketchum in a gym battle, Brock was freed from his duties when his estranged father, Flint, returned to care for the siblings, allowing him to join Ash on his journey. His primary aspiration during the early part of his travels was to become the world's greatest Pokémon Breeder.

Personality-wise, Brock is the most mature, level-headed, and domestic member of the main group. He acts as a caretaker, older brother, and voice of reason for his friends, often mediating disputes and providing guidance. He handles almost all the cooking and cleaning for the group and is highly skilled at preparing food that appeals to both humans and Pokémon. He is well-prepared for any situation, always carrying maps, potions, cookware, and other practical supplies. Despite his wisdom, he has a notable and recurring weakness for attractive women; whenever he sees a pretty girl, particularly Officer Jenny or Nurse Joy, he will enthusiastically attempt to court her, often with grand romantic gestures. This behavior is almost always cut short by a companion who drags him away, such as Misty pulling his ear, or by his own Pokémon. In the Sinnoh region, his Croagunk routinely jabs him with a Poison Jab attack to subdue him and prevent his flirtatious antics.

Throughout the story, Brock serves as a constant and supportive companion to Ash, traveling with him through the Kanto, Johto, Hoenn, and Sinnoh regions. While he is not the primary battler, his experience as a Gym Leader makes him an astute strategist who can analyze battle conditions and explain complex situations to others. Over time, his goal evolves from becoming a Breeder to pursuing a career in Pokémon medicine. In later series, he is shown training to become a Pokémon Doctor, working alongside Nurse Joy, and his nurturing nature finds a new professional outlet. He makes guest reappearances in later seasons, including the Sun & Moon series and the final episodes of Ash's journey, where it is revealed that he has achieved his goal of becoming a Pokémon Doctor.

In terms of abilities, Brock is a highly competent Pokémon trainer and caretaker. He possesses a diverse team of Pokémon, many of which reflect his nurturing personality. His signature and most powerful Pokémon is his Onix, which later evolves into a Steelix capable of Mega Evolution. Other notable Pokémon in his care include a Crobat, which evolved from a Zubat due to their strong bond; a Ludicolo and a Marshtomp, both of which share his flirtatious disposition; and a Sudowoodo that he raised from a Bonsly. He also has a Blissey, which evolved from a Happiny he raised from an Egg, symbolizing his path toward becoming a doctor. His Croagunk is unique for its protective and corrective role, frequently saving Brock from his own romantic impulses. Brock is also notably the tallest of the main characters and possesses distinct physical features, including tanned skin that is darker than other major characters and eyes that are perpetually drawn in a closed, smiling fashion.