Gō is a ten-year-old boy from Vermilion City in the Kanto region who serves as one of the main protagonists of Pokémon Journeys: The Series. He comes from a relatively affluent family, as his parents are programmers who work for a company called Gogo Systems. During his early childhood, his parents were often very busy with their work, leaving Gō to spend much of his time alone at home. This period of isolation led him to fill his time with extensive online research about Pokémon, a habit that contributed to his impressive knowledge base but also stunted his social development. Aside from his childhood friend Koharu, Gō had few other friends growing up, and a past incident where an acquaintance broke a promise led to lingering feelings of betrayal and a reluctance to form new connections.

Gō's entire life trajectory changes at the age of six when he and Koharu attend Professor Oak's Pokémon Summer Camp. During this trip, the two encounter the Mythical Pokémon Mew. This moment leaves a profound impression on the young Gō, who swears that when he becomes a Pokémon Trainer at age ten, he will catch Mew. This event becomes the foundation of his two primary goals: to catch every Pokémon species in every region and, as his ultimate objective, to capture the elusive Mew.

In terms of personality, Gō is often presented as a direct contrast to his partner Ash. Gō is a cool-headed, stylish, and confident city boy who relies heavily on technology, data, and his own analytical skills. He is highly knowledgeable about Pokémon, adept at gathering information, and takes pride in this intelligence, which can sometimes manifest as a know-it-all attitude. This confidence, however, masks his inexperience as a trainer and his lack of social skills. He can be easily flustered or embarrassed, and he often misunderstands the feelings of both people and Pokémon due to spending most of his childhood focused solely on his research. For instance, he has a tendency to misinterpret playful banter as genuine insults and may believe a minor argument could end a friendship permanently. Despite these challenges, Gō has a strong moral core and loves Pokémon, often rushing to help those in need, even if he initially struggles to form deep emotional bonds with the ones he catches.

Gō’s role in the story begins when he chases the Legendary Pokémon Lugia through Vermilion City. He manages to grab onto Lugia, where he meets Ash for the first time. After their adventure, the two are offered positions as research fellows at the Sakuragi Institute, led by Professor Sakuragi, Koharu's father. This role allows Gō and Ash to travel across all known regions to research Pokémon phenomena, with Gō focusing on his personal quest to catch every Pokémon he encounters. Unlike traditional trainers who weaken Pokémon through battle, Gō’s signature method is to throw a Poké Ball directly at a Pokémon, often using a curveball technique. While efficient, this method can be unreliable and showcases his initial lack of battling knowledge.

A major part of Gō’s development involves his key relationships. His friendship with Koharu dates back to childhood, and while she often gets exasperated by his antics, she genuinely looks out for him. Professor Sakuragi serves as a mentor, having known Gō since he was young and offering him the research position that enables his journey. The most significant relationship is with Ash. Despite their contrasting personalities, Gō quickly accepts Ash as a friend and comes to deeply admire him, viewing Ash as a role model for his determination, his unorthodox battle instincts, and his strong bond with Pikachu. Through Ash, Gō learns the value of friendship beyond his small childhood circle and begins to understand battling as more than just a calculation of type advantages.

Gō’s development is most clearly illustrated through his relationship with his first partner Pokémon. Initially, Gō rejects the traditional starter Pokémon offered by Professor Sakuragi, insisting that Mew will be his first. However, during a trip to the Galar region, he encounters a mischievous Scorbunny. After the Scorbunny proves its loyalty and courage by helping Gō stop a rampaging Gigantamax Snorlax, Gō changes his mind and catches it as his official first partner. This marks the beginning of his growth as a trainer. As Scorbunny evolves into Raboot, the relationship becomes strained. Raboot develops a cooler, more independent demeanor and a fervent desire to become a stronger battler, while Gō initially fails to understand this need, preferring to focus on catching. Through conflicts where Raboot runs off to train alone and Gō considers leaving it behind for its own happiness, the two eventually reconcile and learn to understand each other's passions, strengthening their bond. Raboot later evolves again into Cinderace, becoming Gō's most powerful and trusted partner.

Gō also owns a Rotom Phone, which houses a Rotom and serves as his primary tool for research and Pokédex data. He is a skilled researcher but has notably poor climbing skills, a weakness that often requires Ash to help him. Over time, Gō’s battling ability improves from a by-the-book reliance on type advantages to a more flexible and instinctive style after observing Ash. His journey also eventually leads him to join a special investigation team called Project Mew, where he works alongside other trainers, including a former friend named Horace, in high-level missions to find and encounter Mythical Pokémon, bringing him one step closer to his ultimate goal of catching Mew.