His achievement was the setting up of a school that produced statemen with a strong sense of state and duty, known as Rujia, the 'School of the Literati'.
During the Warring States Period and the early Han dynasty China grew greatly and the need for a solid and centralized corporation of government officers able to read and write administrative papers arose. As a result Confucianism was promoted and the corporation of men it produced became an effective counter to the remaining landowner aristocrats otherwise threatening the unity of the state.
Since then Confucianism has been used as a kind of "state religion", with authoritarianism, legitimism, paternalism and submission to authority used as political tools to rule China.
In fact most emperors used a mix of legalism and Confucianism as their ruling doctrine, often with the latter embellishing the former. They also often used different varieties of Taoism or Buddhism as their personal philosophy or religion.