Keisuke Takahashi began as a hot-headed former bosozoku introduced to street racing by his older brother, Ryosuke Takahashi. He joined the Akagi RedSuns, driving a Mazda RX-7 Type R (FD3S), becoming their second-best driver and earning the nickname "The Rotary Brothers" with Ryosuke due to their rotary engines. His early racing style was emotionally charged, marked by an intense dislike of losing. This became starkly evident after consecutive defeats by Takumi Fujiwara's Toyota AE86 on Mount Akina, shattering his pride and fueling an obsessive drive to improve for a rematch. After the RedSuns disbanded, he joined Project D as the uphill ace, partnering with his former rival Takumi. Under Ryosuke's mentorship, he significantly developed, learning to prioritize control and precision over raw emotion. This evolution was demonstrated in victories across Japan, including a final corner overtake using the outer sidewalk against Takeshi Nakazato's Skyline GT-R on Myogi, and a tactical feint maneuver to defeat Seiji Iwaki on Akagi. Other notable opponents he defeated were Wataru Akiyama, Smiley Sakai, Kyoko Iwase (disrupting her turbo boost with a slight bump), Kozo Hoshino, and Go Hojo (who spun out from tire grip loss). Following Project D, Keisuke pursued a professional racing career, achieving one Japanese Super Formula title and three GT Super Series victories. He eventually retired and transitioned into business, becoming CEO of TK Mach Corporation, dealing in automotive parts and real estate. Despite retirement, he maintained racing connections, recording unbeaten demo runs for the MFG (MF Ghost) series in his Mazda RX-7 FD3S; these stood as course records for years until surpassed. He also mentored young drivers like Sena Moroboshi in his brother's "Dream Project," imparting advanced techniques such as sensory driving exercises on Mount Akagi. Personally, he married and had children. His relationship history included a brief romantic interest in fellow RX-7 driver Kyoko Iwase, though he prioritized racing goals over pursuing it. His personality evolved from a volatile, pride-driven youth to a more measured and analytical figure in later years, though he retained his competitive spirit. Documented traits include a height of 182 cm, weight of 63 kg, fondness for his RX-7, and dislikes including the Nissan Skyline GT-R and certain fashion trends.