He started his career as an Assistant Officer (從事) under Liu Zhang, the Governor of Yi Province (covering present-day Sichuan and Chongqing).
Zhou Qun told him that he would gain the territories in Hanzhong Commandery but not its people, and advised him to not send a detachment of his main army to attack the enemy.
[8] At the time, Zhang Yu, who was known for being better than Zhou Qun in divining the future, advised Liu Bei against launching the Hanzhong Campaign.
After the successful conquest of Hanzhong, Liu Bei nominated Zhou Qun as a maocai (茂才; a cultivated talent recommended for a government post),[9] probably to commend him for his earlier advice, but did not do the same for Zhang Yu.
Zhang Yu once privately made a prediction: "In the gengzi year, the ruling dynasty will change and the Liu clan's reign will come to an end.
[14] Zhang Yu once foretold Deng Zhi's future by telling him that he would rise to the position of General-in-Chief (大將軍) and gain a marquis title after he turned 70.