Qin Lang was born in the late Eastern Han dynasty and his ancestral home was in Xinxing Commandery. His father was Qin Yilu, a former subordinate of Lü Bu, a warlord who lived in the late Eastern Han dynasty. His mother was Qin Yilu's ex-wife, Lady Du, who was taken by the warlordCao Cao as a concubine after Lü Bu's defeat and death at the Battle of Xiapi in 198. At a young age, Qin Lang accompanied his mother and joined Cao Cao's household. Cao Cao adopted Qin Lang as a son and doted on him. Once, during a banquet, Cao Cao told his guests, "Would someone love his foster son in the same way as I do?"
During Cao Rui's reign
When Qin Lang grew up, he travelled around China and did not take up any appointments in the civil service or in the military. After Cao Cao's death in 220 CE, he remained in the state of Cao Wei – founded by Cao Cao's son and successor, Cao Pi – during the Three Kingdoms period. In 227, after Cao Rui, Cao Pi's son, ascended the Wei throne upon the death of his father, Qin Lang was appointed General of Valiant Cavalry and Official Who Concurrently Serves in the Palace, and he constantly accompanied Cao Rui on his tours. During his reign, Cao Rui liked to pick on people's wrongdoings, and many people who committed minor offences were executed by him. Qin Lang never advised Cao Rui against his ways, nor did he recommend any talents to the Wei imperial court, but he was still nonetheless deeply favoured by the emperor, who often consulted him and called him by his childhood name "Ah-su". Cao Rui also showered gifts on Qin Lang and even had a large residence constructed in the capital Luoyang for the latter. Other officials were aware that Qin Lang was not much of a capable and talented person, but they knew that he was close to the emperor Cao Rui, so they often bribed him and attempted to curry favour with him. In return, Qin Lang used his status and close relationship with Cao Rui to help these officials get promotions and even titles of nobility. In the autumn of 233, the Xianbei chieftain Budugen, who had previously surrendered to Wei, rebelled and collaborated with another Xianbei leader Kebineng. Bi Gui, the Inspector of Bing Province in Wei, led an army from his province to attack the Xianbei but was defeated. Budugen and Kebineng became more united after that and they constantly raided Wei's northeastern borders. Cao Rui ordered Qin Lang to lead another army from the capital to attack the Xianbei, and Qin succeeded in driving the enemy far into the deserts in the north. By winter, Budugen's subordinates had surrendered to Qin Lang in Bing Province, so Qin and his army returned to Luoyang. In late 238, Cao Rui became seriously ill, and he wanted to appoint Cao Yu, Xiahou Xian, Cao Shuang, Cao Zhao and Qin Lang to help him administer state affairs in his absence. Xiahou Xian and others had disagreements with the ministers Liu Fang and Sun Zi, so Liu Fang and Sun Zi managed to persuade Cao Rui to change his decision. Cao Rui then appointed Cao Shuang and Sima Yi as the regents instead, while Qin Lang and the others were dismissed from office.
