Lu Mao was a younger brother of
Lu Xun. His
ancestral home was in
Wu County,
Wu Commandery, which is in present-day
Suzhou,
Jiangsu. At a young age, he was already known for being a keen learner and for valuing righteousness. Some of his friends – Chen Rong (),
Puyang Yi, Jiang Zuan () and Yuan Di () – were from humble backgrounds but had great ambitions. Lu Mao, who was from a more affluent family, often shared his wealth with them. Xu Yuan (), who was also from Wu Commandery, moved to
Kuaiji Commandery. He had never met Lu Mao before, but before his death, he wrote to Lu Mao and requested Lu to help him take care of his young son. Lu Mao obliged, had a proper tomb constructed for Xu Yuan, and adopted Xu Yuan's son. Lu Mao's
second cousin-uncle,
Lu Ji, died early, leaving behind two sons and one daughter who were still very young then. Lu Mao adopted Lu Ji's children and raised them. They left him only after they reached adulthood. The commandery officials wanted to recruit Lu Mao to join the civil service but he refused.
Ji Yan, one of Lu Mao's colleagues, was notorious for being very critical of others. When he was serving as a Master of Writing in the Selection Bureau (選曹尚書; i.e., the equivalent of a present-day
human resources officer), he often went around spreading news of scandalous incidents involving his colleagues just to show how harsh he could be in criticising others. Lu Mao advised him to forgive others for their past transgressions and focus on praising them for their virtues and contributions instead. He also urged Ji Yan to promote and strengthen a civil culture that might be beneficial to Wu's future developments. Ji Yan ignored Lu Mao's advice and eventually met his downfall. In 232, Lu Mao was summoned to the Wu imperial court and was appointed as a Consultant () and Master of Writing in the Selection Bureau. The Wu emperor
Sun Quan hated the warlord
Gongsun Yuan for breaking his promise to ally with him against Wu's rival state,
Cao Wei. He planned to personally lead an army to attack Gongsun Yuan. Lu Mao wrote a
memorial to Sun Quan to dissuade him from launching the campaign, in which he explained the perils of travelling far to attack a distant enemy and pointed out some negative consequences that may result from the campaign, such as the
Shanyue tribes taking advantage of Sun Quan's absence to cause trouble in the Wu region. Sun Quan disagreed with Lu Mao. Lu Mao then wrote another memorial to Sun Quan, advising him to refrain from attacking Gongsun Yuan, and focus on maintaining stability in Wu and making long term defence preparations instead. Sun Quan felt that Lu Mao was very sincere when he wrote the memorial so he abandoned the idea of attacking Gongsun Yuan. Wen Renmin (), a man from the same hometown as Lu Mao, once visited the Wu capital. He received a grand reception that was even better than that normally received by nobles. Lu Mao thought that this was inappropriate according to
Confucian rules of propriety because he believed the level of the reception should be based on the person's social status. He was proven right later. He died in 239. ==Family and relatives==