He hailed from Pingling 平陵 (near modern Xiangyang 咸陽, Shaanxi) and was a commandant (sima 司馬) of the crossbows during the reign of the usurper Wang Mang 王莽 (8-22 CE). He participated in the campaigns against Zhai Yi 翟義 and the rebels of the Red Eyebrows 赤眉. For his military merits he was given the title of Baron of Jianwu 建武男 and awarded the title of General of the Waves (boshui jiangjun 波水將軍).
He finally surrendered his troops to the Gengshi Emperor 漢更始帝 (r. 23-25 CE) Liu Xuan 劉玄 and secured the westernmost commanderies for the Han dynasty. The highest officials of the five commanderies of Hexi 河西 (approx. modern Gansu) made him their highest military commander. After the defeat of Liu Xuan he first sided with Wei Ao 隗囂 before he became aware that Liu Xiu 劉秀 (the eventual Emperor Guangwu 漢光武帝, r. 25-57 CE) was the strongest of the men competing for the power of the empire.
Dou Rong declared his submission under Liu Xiu, who founded the Later Han dynasty, and was appointed regional governor (mu 牧) of the province of Liangzhou 涼州 (modern Gansu).
In 32 CE, Dou Rong took part in Emperor Guangwu's campaign against Wei Ao. For his successful support, Dou Rong was granted the title of Marquis of Anfeng 安豐侯 and was appointed regional governor of Jizhou 冀州 (approx. modern Hebei), Grand Minister of Works (da sikong 大司空) and representative chamberlain for the palace garrison (daixing weiwei 代行衛尉).
His whole family was bestowed so much honours that the Dou family belonged to the wealthiest and mightiest families of the empire. Dou Rong was forced to retire when the son of his cousin was executed because of a crime he had committed. He died shortly later in the capital Luoyang 洛陽.