Chiharu is shown to be quite reckless, once breaking his own arm during a match in the Maximum Tournament to intimidate his opponent, then winning said match with only one arm. He seems to have no real concern for his well-being and often will put himself at risk during fights.
After the time skip, Chiharu seems to have calmed down. He casually strolls in-between two men wielding knives and advises them to fight fairly without weapons.
Chiharu Shiba reveres Kaoru Hanayama and considers him to be his superior, even bowing to the young Yakuza Boss after Kaoru was defeated by Katsumi Orochi during the Maximum Tournament, and dedicating his fight against Iron Michael to Kaoru.
Later, during Kaoru's fight with Spec, Chiharu's words echo out as Hanayama Kaoru breaks through Spec's attack, thus hinting at a mutual respect.
Shiba is extremely durable and has very powerful will. He participated in the Maximum Tournament. Shiba have an incredibly tough skull and often uses a headbutts. He is also known for using attacks with his own face.
He is a street fighter that doesn't seem to feel pain. It is unknown whether Shiba trained any form of combat, but probably he just uses his brute force. In the fight with Kohei Hatanaka, Shiba managed to break his own left arm to intimidate his opponent, then Chiharu proceeded to beat him mercilessly. Shiba also uses dirty tactics sometimes.
Shiba also seems to be a natural at using the endorphin skill, which allowed him to beat 100 men in a fight after he was hit by a motorbike. After his collision with the bike, Shiba comments that he, "feels his power rising," and then continues to fight. Although this was shown in the anime's second season, it is yet to be confirmed if Shiba actually uses his endorphins.
Another example of Shiba's use of the endorphin skill is in his fight against Iron Michael, the current World Heavyweight Boxing Champion, during the Maximum Tournament Arc. He used several dirty tactics during the fight but was eventually overwhelmed by the boxer's power. However, during the fight, as Shiba lay seemingly defeated, the overhead lights of the ring reminded Shiba of the battle against a rival biker gang where he was hit with the speeding motorcycle. This causes him to comment that, "it will be alright," and he continues to fight with even greater ferocity.
Although he is beaten severely thanks to his lack of formal training (receiving many blows to the head and what looks like a dislocated eye), Shiba wins the match by breaking Iron Michael's knuckles with his forehead, rendering Shiba unconscious.