Bart is introduced as a young boy navigating the harsh, post-apocalyptic wasteland. Initially, he is a mischievous and opportunistic thief, having left the home of his adoptive mother, Toyo, so that she could focus her limited resources on caring for younger orphans. His primary motivation for survival is simply finding his next meal, and he possesses a cunning, street-smart demeanor that has allowed him to endure the brutal environment.

Bart first encounters Kenshiro while imprisoned for attempting to steal food. Witnessing Kenshiro's immense strength, Bart decides to follow him, not out of loyalty, but because he sees the powerful martial artist as a reliable source of food and protection. At this stage, he is brash, insensitive, and self-serving, often trying to profit from Kenshiro's heroic deeds. However, as he travels with Kenshiro and the young girl Lin, Bart is exposed to great tragedy and the selfless courage of his mentor. This journey profoundly changes him; he sheds his cynical shell and rediscovers his innate kindness and sense of justice, growing into a mature and virtuous companion. He looks up to Kenshiro like an older brother, and in turn, Kenshiro comes to view Bart as a younger sibling.

Following a significant passage of time, Bart reappears as a handsome and muscular young man. He has become the co-leader of the Hokuto Army, a resistance movement fighting against the tyrannical Imperial forces led by Jakou. Now driven by a desire to change the world and protect the innocent, Bart demonstrates strong leadership qualities and personal courage. He has also fallen in love with Lin, who fights alongside him. While not a master martial artist like Kenshiro, Bart is a capable fighter in his own right, relying on weapons such as crossbows and maces, as well as cunning tactics to overcome his limitations. His resourcefulness extends to a talent for fixing and driving mechanical vehicles, most notably a dune buggy that serves as transportation.

The depth of Bart's character is most evident in his selfless devotion to Kenshiro and Lin. When Lin is placed under a curse that causes her to fall in love with the first person she sees, Bart is prepared to let that person be Kenshiro, believing his hero deserves happiness. In the story's final arc, consumed by guilt that Lin's feelings for him are not genuine, Bart uses his limited, observed knowledge of Hokuto Shinken to erase her memory, hoping she can freely choose Kenshiro. He later confronts a vengeful enemy from Kenshiro's past, Bolge, posing as Kenshiro to protect his friend while Kenshiro suffers from amnesia. Bart endures severe torture but refuses to break, willing to die so that Bolge believes the real Kenshiro is dead. Though mortally wounded, Bart's sacrifice is not in vain; Kenshiro ultimately revives him using his secret martial arts techniques, allowing Bart and Lin to finally live together in peace.