Cheng entered the national university in 1056, and received the "presented scholar" degree in 1059. He lived and taught in Luoyang, and declined numerous appointments to high offices. In 1086, he was appointed expositor-in-waiting and gave many lectures to the emperor on Confucianism. He was more aggressive and obstinate than his brother, and made several enemies, including Su Shi, the leader of the Sichuan group. In 1097, his enemies were able to ban his teachings, confiscate his properties, and banish him. He was pardoned three years later, but was blacklisted and again his work was banned in 1103. He was finally pardoned in 1106, one year before his death.
A well known chengyu 程門立雪 refers to an incident when two men (Yang Shi and You Zuo) requesting to be taken on as his disciples stood in the snow for hours at his door and became renowned examples of the Confucian virtues of devotion to learning and respect for one's master.
Cheng Yi is widely believed to be responsible for the rise of the cult of widow chastity. He argued that it would be improper for a man to marry a widow since she had lost her integrity. On the question of widows who had become impoverished due to the death of their husbands, Cheng stated: "To starve to death is a small matter, but to lose one's chastity is a great matter." The practice of widow chastity that became common in the Ming and Qing dynasty would led to hardship and loneliness for many widows.