Guo Zuo's grandfather Guo Yi. Guo Yi's uncle, Guo Qing, was an official of the former Qin Dynasty. He was in charge of the military affairs of Youzhou and the secretariat of Youzhou. Guo Xing, son of Guo Qing, was killed by the right servant of Northern Yan Shangshu. Guo Sheng, the son of Guo Xing, is a general in Beiyan Town and a high official. Guo Yi was Zhang Yue of Stuart Ho Choi in the Northern Wei Dynasty, the first aristocratic family in the North. He is the secretariat of Xuzhou, a fake Yuci Hou. Guo Yi once married Ho Choi, a native of Qinghe, and had two daughters, and one daughter with Cui Hao's brother.
In the 11th year of Taiping Zhenjun (450), Cui Hao was ordered to make up the national history, which angered the Northern Wei Emperor Tuoba Tao and was exterminated. His in-laws Taiyuan Guo also passed away. Guo Zuo's father Guo Hongzhi died without guilt, but Guo Zuo's death and escape were spared. At that time, he was two years old. Therefore, although Guo Zuo was born in a famous family, he lived a lonely and poor ordinary villager life when he was young. However, Guo Zuo devoted himself to reading, dabbling in classics and studying Cui Haozhi's calligraphy, and his letters and articles gradually became famous all over the world. At the age of 20, he became the chief bookkeeper of Bingzhou and was appointed as a secretary by Sun, the secretary of the Secretariat. At the same time, he supported each other with his cousin Wang Xiyan, the magistrate of Taiyuan, and finally revived the Guo family business in Taiyuan. At that time, the Xianbei regime in the Northern Wei Dynasty still retained the remnants of clan system and slavery, and its backward rule constantly aroused the resistance struggle of the people in the Central Plains. In order to adapt to the advanced culture of the Central Plains, further strengthen the alliance with the Han landlords in the Central Plains, and consolidate and expand the regime of the Northern Wei Dynasty, Guo Zuo and other Korean landlords and bureaucrats, such as Wang Su, Wang Su, Wang Ling-fu and Cheng Ling-fu, formed reformists to assist Emperor Xiaowen in carrying out a series of sinicization reforms. In the 19th year of Taihe (495), Emperor Xiaowen moved his capital from Pingcheng (now Datong City, Shanxi Province) to Luoyang. Guo Zuo, who actively participated in the planning of moving the capital, was named as an absolutely moving photon. Later, he moved away to ride a regular waiter and still led the yellow door. At that time, Emperor Xiaowen was determined to reform, imitated the traditional laws and regulations of the Central Plains, and inherited the popular gate valve system in the Central Plains. In addition, he moved the capital to create grass-roots campaigns, military conquest continued, and internal and external planning strategies were very complicated. At this time, Guo Zuo was ordered to be a staff officer, engaged in the annotation of classics, the evaluation of family status and the evaluation of official rank, and made great achievements, especially presiding over annotations, which won the appreciation of Emperor Xiaowen. When Emperor Xiaowen hosted a banquet for officials, he raised a glass to persuade Guo Zuo to drink, saying, "Guo Zuo is worried about his work and never deceives me." It can be seen that Emperor Xiaowen has great trust in Guo Zuo. Because of this, Guo Zuo has been retained by Emperor Xiaowen and became an important adviser. After Emperor Xiaowen's personal expedition to the Southern Dynasties, Guo Zuo was appointed as the middle assistant, and he was promoted to an uncle.
In the 23rd year of Taihe (499), Emperor Xiaowen died. Emperor Xuanwu, who was only 16 years old, inherited the throne. It was recommended by Wang Yuanxi of Xianyang, who served as the assistant government, and Guo Zuo also served as the official department minister, in the state. In the second year of Jingming (50 1), after Xuan Wudi took office, Guo Zuo continued to be reused. Once, in order to escape punishment, Xuan Wudi wrote a letter to a traitor, saying that if the traitor "can never escape, his brother will take his place". Guo Zuo thought it was inappropriate, so he bluntly remonstrated and said, "It's not cool to use the law to stop rape. Foolish words say that sinners flee, stop moving their wives, leave their bodies, and stay in the name forever. Jade Qing is inevitable, and the treacherous road is self-destructive. " Xuan Wudi adopted Guo Zuo's opinion. This has played a certain role in avoiding the restoration of cruel criminal law and maintaining the reform achievements of Emperor Xiaowen. Soon, Guo Zuo became a full-time official minister. At that time, the politics of the Northern Wei Dynasty had become increasingly corrupt, and there were many people seeking officials among the gentry, but Guo Zuo was basically incorruptible. He attaches great importance to selecting officials and employing people. Whenever selecting officials, he must carefully examine and weigh them. Even if he finds talent, he will think twice before deciding to use it. Therefore, the officials he chooses are generally more competent. However, it often attracts people's disgust.