Duke Zhao of Lu (561-510 BCE), named Chou, was posthumously titled "Duke Zhao," the son of Duke Xiang of Lu and ruler of the State of Lu. In 542 BCE, when Duke Xiang of Lu died, Ji Wuzi installed the young noble Chou as ruler, known as Duke Zhao. At that time, the governing power of Lu was in the hands of the Ji family, and Duke Zhao held only the title of ruler. In the fifth year of Duke Zhao's reign (537 BCE), Ji Wuzi divided the ducal court into four parts, with the Ji family controlling two, and the Shu and Meng families each taking one. That same year, Duke Zhao visited the State of Jin, flawlessly observing diplomatic etiquette; Duke Ping of Jin praised his familiarity with ritual, but the grand master Nü Shu Qi commented that Duke Zhao understood formal rites (Yi) but not true ritual propriety (Li), saying that Li lies in guarding one's state, implementing its decrees, and not losing the people's hearts. The ducal court of Lu was divided into four, decrees were issued by the Three Huan families (descendants of Duke Huan), and the people's loyalty was already lost, leading to a prophecy that he would lose his state.
In the twenty-fifth year of Duke Zhao of Lu (517 BCE), the conflict between the ducal house and the Ji clan intensified. Duke Zhao personally led troops to attack the Ji clan but was instead defeated by the combined forces of the Three Huan families, forcing him to flee to the State of Qi. The following year, Duke Jing of Qi attacked Lu, capturing the city of Yun (east of present-day Yuncheng County, Shandong), and settled Duke Zhao there. During Duke Zhao's exile, Ji Pingzi (head of the Ji clan) acted as regent, handling state affairs.
Duke Zhao of Lu was capricious in character, having once violated the ritual rule against marrying within the same clan by taking a wife from the State of Wu, who shared the same surname—an act widely criticized at the time. When Confucius was asked whether Duke Zhao understood Li (Propriety), he replied that he did, but others immediately cited this incident to refute him, forcing Confucius to admit his mistake. The people of Lu showed little sympathy for the Duke's exile, believing his many faults had caused the populace to forget their ruler. In 510 BCE, Duke Zhao died of illness in Qianhou of Jin (present-day Cheng'an County, Hebei), and the Ji family installed his younger brother, Prince Song, as ruler—Duke Ding of Lu.