Ishikawa serves as the information warfare and technology specialist for Public Security Section 9. His expertise lies in cyber infiltration, hacking, intelligence gathering, and data analysis, making him a crucial asset in the team's operations against cybercrime and political corruption. He is characterized by his physical appearance, which includes a large, full beard and perpetually unkempt hair, and he is depicted as the eldest among Section 9's field operatives.

His background reveals a long history with the core members of Section 9. He formerly served with Motoko Kusanagi and Batou in South America as part of the Ground Self-Defense Forces in the Japanese United Nations contingent. This shared military experience made him one of the earliest recruits to be personally selected for Section 9, and as a result, he possesses a deep, seasoned understanding of the Major, including her personal dislikes. Ishikawa is known for his calm, pragmatic, and laid-back personality. He approaches problems with logic and patience and has a cynical sense of humor, which makes him one of the more grounded and reliable members of the unit. He is also known for delivering long, technically detailed expository speeches to his teammates to explain complex story developments.

In his private life, Ishikawa owns and operates a pachinko parlor called Parlor Ishikawa. He is known to occasionally commandeer the cyberbrains of the elderly patrons in his parlor to assist with heavy-duty data processing, a method that seems to cause them no harm or awareness. In contrast to heavily cybernetic members like Batou, Ishikawa appears to have a low prosthetic body percentage. His dialogue and notably longer recovery times from physical injuries suggest he is one of the least augmented members of Section 9, relying more on his natural intelligence and strategic mind than on enhanced combat capabilities.

As a result, his role in the story is primarily a supportive one. He is most often seen in Section 9's information analysis room rather than on the front lines. He coordinates efforts from the base, providing essential remote support to field agents. He is almost never shown in direct combat, though he is not entirely defenseless, having once fired a shoulder-mounted cannon to disable an armored vehicle. When captured during a political purge, he was easily taken into custody by commandos, highlighting his physical vulnerability compared to his more augmented comrades. Ishikawa shares a close professional relationship with Batou, often engaging in friendly banter, and has a strong bond based on mutual respect with Chief Daisuke Aramaki. He progressively came to respect the more traditional detective skills of his younger teammate, Togusa. Despite his lack of physical prowess, Ishikawa is deeply loyal and dedicated to his team, ensuring they have the intelligence and cyber support necessary to complete their missions successfully.