[1] Dou Zhengu passed the imperial examinations in the Jinshi class during the Tongguang era (923-926) of Later Tang's founding emperor Li Cunxu, and he was made the secretary general for Wanquan County (萬全, in modern Zhangjiakou, Hebei).
After the mourning period was over, he was made an assistant to Shi Jingtang the military governor (Jiedushi) of Hedong Circuit (河東, headquartered in modern Taiyuan, Shanxi).
He was later made the minister of justice (刑部尚書, Xingbu Shangshu), before being sent out of the imperial government to serve as the military prefect (團練使, Tuanlianshi) of Ying Prefecture (潁州, in modern Fuyang, Anhui), where he remained for a year, before being recalled to the imperial government to again serve as minister of justice.
(Dou Zhengu's activities during this period were not clearly stated in traditional histories, although he presumably, along with other Later Jin officials, submitted to the Liao emperor.)
Liu Zhiyuan, then the military governor of Hedong, initially postured that he would submit to Liao, but then declared himself emperor (of a new state later known as Later Han).
With Liu and many others resisting his rule, Emperor Taizong withdrew from the Central Plains region and died on the way back to Liao proper.
He entrusted his son Liu Chengyou to Su Fengji, Yang Bin, Shi Hongzhao, and Guo Wei, and then died.
They had discussed and resolved that, because of frequent Liao incursions and the inability for the circuits to coordinate their defenses, Guo Wei should be sent to Yedu (鄴都, in modern Handan, Hebei) to serve as its defender (as well as the military governor of Tianxiong Circuit (天雄, headquartered at Yedu) to coordinate the defense against Liao.
Su Fengji opposed, pointing out that there had been no precedent to allow a military governor to continue to retain chief of staff title.
At the feast, Shi, when toasting Guo, spoke in a harsh voice, "How could there have been opposition when we discussed this matter yesterday at the imperial gathering?
Shi responded, again in a harsh voice, "To settle the state, it takes long spears and large swords.
He conspired with his uncle Li Ye (李業), as well as his favorite attendants Nie Wenjin (聶文進), Hou Kuangzan (後匡贊), and Guo Yunming (郭允明), to kill Yang and the others.
Despite this realization, he did not accept his mother Empress Dowager Li's advice to try to maintain a pretense of emperor-subject relations with Guo Wei; rather, commissioning Liu Zhiyuan's half-brother Murong Yanchao as the commander of the imperial troops, he decided to confront Guo Wei personally.
Su Yugui and Dou hid themselves, but after Guo entered Daliang, he located them and restored them to their chancellor positions.
[9]) Shortly after Guo Wei took the throne, he bestowed on Dou Zhengu the greater chancellor title of Shizhong (侍中).
[9] Not long after, with the senior statesman Feng Dao becoming a chancellor again, Dou was put in charge of editing imperial histories.
[10] After the Later Zhou throne was seized by the general Zhao Kuangyin, who established Song dynasty as its Emperor Taizu, Dou Zhengu was summoned back to the imperial court given his prior status as one of the Three Excellencies.
He went to see Fan Zhi, who had remained a chancellor under the new Song emperor, requesting that he be given an honorary post as an advisor to the Crown Prince so that he could attend imperial meetings.