Ji Kangzi (died 468 BCE), also known as Jisun Fei, with the surname Ji, clan name Ji, personal name Fei, and posthumous title "Kang," is historically called Ji Kangzi. He served Duke Ai of Lu, during a time when the Lu ducal house was weak and the Three Huan families led by the Ji clan were powerful. As the head of the Ji clan, Ji Kangzi held high rank and great power, making him a powerful minister of Lu.
At that time, the State of Lu survived in the narrow space between the two great powers, Qi and Wu, and its situation was not favorable. In the seventh year of Duke Ai of Lu (488 BCE), King Fuchai of Wu attacked Qi and held a covenant meeting with Lu at Zeng (northwest of present-day Cangshan, Shandong), forcing Lu to contribute one hundred lao (sacrificial animals; according to Zhou Li [Rites of Zhou], tribute should not exceed twelve). Ji Kangzi sent Zi Gong (a wealthy merchant and eloquent disciple of Confucius) to persuade the Wu king and Grand Steward Pi, but failed; Lu was compelled to comply. When Grand Steward Pi of Wu summoned Ji Kangzi to court, he refused to attend. In the eleventh year of Duke Ai of Lu (484 BCE), Qi attacked Lu. Shusun and Mengsun, resenting Ji's monopoly of power, refused to follow Ji Kangzi's orders to keep the Qi forces outside the borders. Ji Kangzi sent Ran You (a capable disciple of Confucius) to lead the army, defeated Qi, and won a great victory. Subsequently, they joined forces with Wu and defeated Qi at Ailing, a battle known historically as the "Battle of Ailing." However, after this battle, Ji Kangzi intensified military preparations to guard against another Qi invasion. When he asked Ran You where he had learned his military skills, Ran You replied that he had learned them from Kong Qiu (Confucius). Ji Kangzi then sent envoys to welcome Confucius back to Lu from the State of Wei. In the twelfth year of Duke Ai of Lu (483 BCE), Ji Kangzi appointed Ran You to reform the land tax and increase levies, further accelerating the process of the collapse of Li (Propriety) and music.
Ji Kangzi (a senior official of the State of Lu) asked Confucius about governance. Confucius replied, "Governance (Zheng, governance) means to be upright (Zheng, upright). If you lead by example on the right path, who would dare to stray from it?" Ji Kangzi then asked, "What if we kill those who are not on the Way (Dao, way) to draw near to those who are on the Way?" Confucius opposed governing through punishment and advocated for rule by virtue (De, virtue), saying that if those in high positions govern affairs well, the common people will not rebel. Troubled by the prevalence of thieves, Ji Kangzi sought Confucius's advice. Confucius replied, "If you yourself were not greedy for wealth, even if you rewarded them for stealing, they would not do so."
In the spring of the 27th year of Duke Ai of Lu (468 BCE), Ji Kangzi (a noble of the State of Lu) passed away.