He hailed from Shangbang 上邦 (modern Tianshui 天水, Gansu), and became a rider in the Palace Guard cavalry (Yulin qi 羽林騎) because of his expertise in horsemanship and bowshooting. He was a very brave and intelligent person, excelled in the military writings and knew a lot about the native peoples of the northwest. During the reign of Emperor Wu 漢武帝 (r. 141-87 BCE), he belonged as acting commander (jia sima 假司馬) to the staff of general Li Guangli 李廣利 during his campaigns against the steppe federation of the Xiongnu 匈奴. When Li Guangli was assailed by a hoard of Xiongnu, Zhao Chongguo rescued his superior by a fierce attack. He was rewarded with the title of inner gentleman (zhonglang 中郎) and then promoted to aide to the General of Chariots and Cavalry (cheji jiangjun zhangshi 車騎將軍長史).
During the reign of Emperor Zhao 漢昭帝 (r. 87-74 BCE) he lead a campaign against the Di tribes 氐 of Wudu 武都 and again against the Xiongnu, during which he captured the khan (wang 王) Xiqi 西祁. The was appointed Leader of the court gentlemen (zhonglangjiang 中郎將) and Commandant of the Imperial Gardens (shuiheng duwei 水衡都尉). He assisted General-in-chief (da jiangjun 大將軍) Huo Guang 霍光 bringing Emperor Xuan 漢宣帝 (r. 74-49 BCE) to the throne, and was therefore given the title of Marquis of Yingping 營平侯. In 73 BCE he was appointed general with seat in the colony of Pulei 蒲類 in the Western Territories 西域. For his successful campaign against the Xiongnu he was granted the title of Chamberlain for the palace revenues (shaofu 少府).
From 65 BCE on he became the leading general for the campaign against the Qiang tribes 羌. This was necessary because the institution of the Commandant protector of the Qiang (hu Qiang xiaowei 護羌校尉) proved not effective to ward off the Qiang tribes from Han territory. More and more Qiang settled down on Chinese territory, their chieftains allied with the Xiongnu in the north, and threatened the city state of Shanshan 善鄯 and even the commandery of Dunhuang 敦煌. In 61 BCE the various Qiang tribes rose in rebellion against the Han empire, but the chieftain Yiqu Anguo 義渠安國 was defeated and forced to settle down in a restricted area. Zhao Chongguo, in the age of 70 sui took over command over the forces repelling the Western Qiang tribes.
While the governor (taishou 太守) of the commandery of Jiuquan 酒泉, Xin Wuxian 辛武賢, suggested founding military agro-colonies (tuntian 屯田) to repell the Qiang, Zhao Chongguo advocated the use of massed forces to defeat them once and for all, and then to turn towards the north against the Xiongnu and Wuhuan 烏桓. These two federations used the chance of the Han military being engaged in the west, in order to bring trouble to the northern borders of the empire. Emperor Xuan 漢宣帝 (r. 74-49 BCE) adopted Zhao's plan, so that the Qiang of Xianling 先零羌 were defeated first and the "net" Qiang tribes (Han Qiang 䍐羌) soon submitted to the Han army. Their leaders were executed, and the rest of the troops submitted. Only then he suggested founding military colonies in the Gansu corridor. When the campaign was over, Zhao Chongguo asked to be allowed to retire, but the court declined. He died in office.