Lu Ji, courtesy name Gongji, was a native of Wu County in Wu Commandery. His father Lu Kang was Administrator of Lujiang at the end of the Han. At the age of six Lu Ji met Yuan Shu in Jiujiang. When Yuan Shu set out oranges, Lu Ji tucked three of them into his robe, and as he bowed to take his leave they fell to the ground. Yuan Shu said, 'Young Master Lu, do you come as a guest and carry off oranges in your robe?' Lu Ji knelt and answered that he had meant to take them home to give to his mother. Yuan Shu thought him most remarkable. Records, Wu 12 §18
When Sun Ce was in Wu, Zhang Zhao, Zhang Hong and Qin Song were his honored guests, and together they argued that since the four seas were not yet at peace, force must be used to bring order and pacify them. Lu Ji, who being young sat at the lowest seat, called out loudly from afar that in former times Guan Yiwu, as chancellor to Duke Huan of Qi, assembled the feudal lords nine times and set the realm right once, without using war chariots. He added that Confucius had said, 'If people far away do not submit, cultivate civil virtue to draw them,' yet those now debating did not devote themselves to the art of winning people over through the Way and virtue but esteemed force alone, and though he was only a child, he was uneasy at heart. Zhang Zhao and the others thought him extraordinary. Records, Wu 12 §18–19
Lu Ji was imposing in appearance and widely learned, and there was nothing in astronomy, calendrical science and mathematics that he had not surveyed. Yu Fan was an elder of high renown, and Pang Tong was a famous scholar of Jing Province and somewhat older, but both were on friendly terms with Lu Ji. The biography of Gu Shao, son of Gu Yong, records that in his youth Gu Shao was equal in fame to his maternal uncle Lu Ji, and that Lu Xun, Zhang Dun, Bu Jing and others all ranked after them. Records, Wu 12 §20Records, Wu 7 §36–37
According to the Biography of Pang Tong, when Zhou Yu died, Pang Tong escorted his coffin to Wu, and when he was about to return west, people gathered at the Chang Gate, and Lu Ji, Gu Shao and Quan Cong all went there. Pang Tong said, 'Master Lu may be called a slow horse with the strength to run fast.' Lu Ji and Gu Shao told Pang Tong that when the realm was at peace they would appraise the scholars of the whole world together with him, and they formed a deep friendship with Pang Tong. Records, Shu 7 §4–5
When Sun Quan took charge of the government, he summoned Lu Ji and made him Officer of the Memorials Bureau. But because his upright ways made him feared, he was sent out as Administrator of Yulin, given the additional title of Lieutenant General and 2,000 soldiers. Lu Ji was lame, and his aspirations lay in Confucian refinement, so this was not what he wished for. Records, Wu 12 §20
Though he had military affairs to attend to, he did not give up writing; he made the Diagram of the Celestial Sphere, wrote a commentary on the Book of Changes and explained the Taixuan, all of which were handed down in the world. Foreseeing the day of his own death, he composed a piece lamenting that Lu Ji of Wu Commandery, a man of purpose of the Han, had diligently studied the Odes and the Documents in his youth and delighted in the Rites and the Changes when grown, but, having received orders to campaign in the south, fell ill, met misfortune and came to an unhappy fate. He also said that sixty years from then carriages would share the same axle width and writing the same script, and that he regretted he would not live to see it. Records, Wu 12 §21
Lu Ji died at the age of thirty-two. The Records do not give the year of his death. According to the biography of Lu Mao, younger brother of Lu Xun, when his uncle Lu Ji died early, his two sons and one daughter were all only a few years old, so Lu Mao took them in, cared for and raised them, and let them go only after they had grown up. The elder son Lu Hong became Chief Commandant of the Southern Division of Kuaiji, and the second son Lu Rui became Colonel of the Changshui. Records, Wu 12 §22 · 64
In his assessment Chen Shou said that Lu Ji's relation to Yang Xiong's Taixuan was like that of Zuo Qiuming to Zhongni and of Yan Zhou (Zhuang Zhou) to Lao Dan. He added that a vessel as precious as a hulian ritual vessel had been charged with guarding Southern Yue; was this not, too, doing the man harm? Records, Wu 12 §89