Lü Buwei was originally a merchant from Yangdi 陽翟 who had accumulated a tremendeous fortune. The Lord of Anguo 安國君 was the second son and crown prince of King Zhao(xiang) of Qin 秦昭襄王 (r. 306-251). The lord's main wife was Lady Huayang 華陽夫人. His second son was Chu 楚, who stayed as a hostage at the court of the state of Zhao 趙, in the capital Handan 邯鄲. In this place he came in contact with Lü Buwei who was not only rich but also a very skilled intriguer.
Chu was only the second son of the heir apparent, but because Lady Huayang had no son of her own, a better relationship with her would improve Chu's position. Lü Buwei managed to buy the hostage free, and Chu returned to Qin. He immediately established contact with the Lady, offering her a gift of precious jewels, again financed by Lü Buwei. The Lady's intercession made Chu heir of Lord Anchun.
When King Zhaoxiang died, Lord Anchun succeeded to the throne, as King Xiaowen 秦孝文王 (r. 251-250 CE). He died after less than one year of regency, and Chu eventually became king Zhaoxiang of Qin 秦莊襄王 (r. 250-247). Lü Buwei was made Counsellor-in-chief (chengxiang 丞相) and enfeoffed as Lord Wenxin 文信君, disposing of the income of 100，000 households of Luoyang 洛陽, according to other sources the income of 12 districts (xian 縣).
Lü Buwei had a large contingent of retainers from all regions of China. Many were philosophers or experts in universal science. He had his retainers compiled a compendium on the seasons and the cosm which is known as Lüshi chunqiu 呂氏春秋.
Lü Buwei was sent out to crush the resistance of the Lord of Eastern Zhou 東周君, one of the last descendants of the kings of Zhou 周. He also supervised the conquest of the realms of Shu 蜀 and Ba 巴 in modern Sichuan, the region of Hanzhong 漢中, some territories of the state of Chu 楚, and some of the state of Zhao. Lü Buwei planned to conquer all other feudal states to unify the empire.
King Zhaoxiang died soon and was succeeded by his underage son Zheng 政, the future First Emperor of Qin 秦始皇 (r. 246/221-210). Regency was put into the hands of "father" (zhongfu 仲父) Lü Buwei and the Queen Dowager, mother of the young king. The mother had been introduced to Prince Chu (King Zhaoxiang) by Lü Buwei when she was still Lü's concubine.
Some historians, like Sima Qian 司馬遷 in his universal history Shiji 史記 later said that king Zheng was in fact Lü Buwei's son. During the regency of the Queen Dowager, Lü Buwei allegedly continued his sexual relationship with her. She also had a lover called Lao Ai 嫪毐 who had access to her, disguised as a eunuch. She is said to have had two children by him.
In 238, the King was of full age and took over regency. The King immediately had Lao Ai executed and later also banished Lü Buwei to the remote region of Shu, where he took poison in 235.
Archeologists have unearthed a dozen of swords, halberds and bronze weights from the Qin period which bear Lü Buwei's name in their inscriptions. Lü is designated as "Counsellor-in-chief of the state" xiangbang 相邦 (a term later changed into xiangguo 相國 in order to avoid the personal name of emperor Han Gaozu 漢高祖, Liu Bang 劉邦, r. 206-195).