Xu Chu jumped into action against the Yellow Turban Rebellion with his clan, building a stronghold within ramparts. His mighty exploits against the insurgents frightened them away and brought him localised fame. Cao Cao first encountered him during his campaign against the Yellow Turban rebels led by He Yi and Huang Shao. Xu Chu blocked the retreat road of the rebels leader He Yi and easily captured him along with his men. Then, he encountered Cao Cao's stalwart general Dian Wei. He challenged Dian Wei to personal combat. He set his spear under his arm, and they clashed for three days, yet a victor was undecided. With an ambush set, Cao Cao told Dian Wei to pretend defeat in order to capture the bravo. Finally Xu Chu was captured, admired by his intense fighting style, Cao Cao invited him to join his troops. He readily agreed, as he had long desired to serve a great warlord.
     Shortly afterwards, he proved his worth in a surprise attack against Lu Bu. As an introductory gift to Cao Cao, Xu Chu killed the enemy leader Li Feng, and Xue Lan was defeated and retired with his troops. Thus Xu Chu helped Cao Cao recapture Yanzhou. He accompanied Cao Cao in fighting off his enemies, at nearly every major battles he had which most of them were successful. He donned new colors and was put in charge of the imperial guards in the capital. His men were known as the "Tiger Guards."
     In one incident, Xu Chu grew angry when Xu You insulted him saying, "You are a lot of blockheads, not worth talking about." In his anger, he drew his sword and cut him off, then he went to tell Cao Cao the reason of his action. He was a proud warrior and very strict in his duty, which was showed when he refused Cao Ren's entry to Cao Cao's palace strictly in command. He also saved Cao Cao many times when fighting Sun Quan at Ruxukou and Ma Chao near Changan.
     Xu Chu contended with Ma Chao in the battle at Tong Pass. He kept close by his commander amidst the struggle, but Cao Cao was in a poor position and Ma Chao drove him back to the banks of the Wei River. Xu Chu swiftly lifted Cao Cao on his back and made a mad dash for a nearby boat. Rowing as quickly as his arms could pull, he rescued Cao Cao away from the perilous scene. Later he and Ma Chao clashed in hand-to-hand combat. They fought for over two hundred bouts without a certain victor. Stripped of his armor to reveal his brawny physique, Xu Chu ravaged his opponent, engaged his intense fighting style once again. Thereafter he appropriately became known as the "Passionate Tiger." This famous duel placed Xu Chu amongst the greatest fighters of Three Kingdoms period.