Master Meng was an adherent of the Confucian tradition transmitted by Zisi 子思 (Kong Ji 孔伋), a grand-son of Confucius(Kongzi 孔子), and lived in the mid-4th century BCE (the dates range from 385-304 to 372-289), during the Warring States period 战国 (5th cent.-221 BCE). Mengzi, courtesy name Ziyu 子舆 or Ziju 子居, hailed from the small state of Zou 邹 (modern Zouxian 邹县, Shandong). His father died when he was still a child. Mengzi's mother (called "Meng Mu" 孟母) is traditionally venerated as an example of excellent virtue. She moved their home three times to live in a better neighbourhood, and it was herself who taught the young Meng Ke the first lessons of virtual behaviour. Mengzi traveled from court to court and served the rulers of the states of Qi 齐 and Wei 魏, and those of the smaller states of Teng 滕, Xue 薛, and Song 宋. In Wei 魏 (at that time called Liang 梁) he served King Hui 梁惠王 (r. 379-335). Unfortunately most lords appreciated the teachings of thelegalist or military advisers, who suggested strengthening the state by a powerful central government, while Mengzi's teachings of a benevolent and human government seemed too theoretical for them. He was at least able to gain the confidence of the kings Hui of Liang and Xuan of Qi 齐宣王 (r. 342-324) for some time.

After his canonisation in 1083 as "Duke of Zou" 邹国公, and in 1330 as "Ducal Second Saint" (yasheng gong 亚圣公), Mengzi became the second grand master of Confucianism and was named together with Confucius himself as the pair Kong-Meng 孔孟, their teachings as "the way of Confucius and Mencius" (Kong-Meng zhi dao 孔孟之道). During the May Fourth movement 五四运动, Mengzi was attacked as the "second boss of the Confucian shop" (Kongjia dian er laoban 孔家店二老板, Kongdian di er lao 孔店地二老) that, it was said, had contributed to the fossilization of Chinese society and the traditional Chinese world of thought.

Mengzi was such an important teacher of Confucianism that a lot of "annalistic biographies" (nianpu 年谱) have been compiled. The most important are Cheng Fuxin's 程复心 Mengzi nianpu 孟子年谱 from the Yuan period 元 (1279-1368), Tan Zhenmo's 谭贞默 Mengzi biannian lüe 孟子编年略 from the Ming period 明 (1368-1644), and Di Ziqi's 狄子奇 Mengzi biannian 孟子编年 from the Qing period 清 (1644-1911).