Why was Mao Zedong significant to China?

Mao Zedong was significant as the first leader of a unified China following the end of the Qing Dynasty in 1911. After China's last emperor abdicated his throne in 1911, China entered into decades of civil war and the foreign invasion of Japan during World War II. Mao's Chinese Communist Power (CCP) became a strong central party and, for all of his flaws, built the economic and political foundations of the modern Chinese state.
Mao was the single most decisive factor in Chinese politics, economy, and military growth during his rule. Some of the most famous eras in modern Chinese history happened directly due to Mao's initiatives. From 1958-1962, China entered into a Great Leap Forward that brought widespread famine across the country — killing millions. China went from a small military to a nuclear power in 1964 under his rule. In 1966, he initiated a Cultural Revolution that spread chaos throughout the country and did massive damage to China's art, religion, and left millions imprisoned. The Chinese Communist Party today continues to grapple with the immensely potent legacy of Mao. Chinese currency continues to bear his likeness in remembrance of their charismatic founder.

Mao Zedong, or Chairman Mao, was the effective founder of the People's Republic of China (PRC). He ruled China from the PRC's foundation in 1949 until his death in 1976. During this time, he was the prime political figure as well as the dominant theoretician of Chinese Communism. Mao, more than any other individual, was responsible for the development of China as a Communist state. The economic and political direction that the country took was strongly influenced by Mao's ideas, and it was buttressed by Mao's huge personal charisma and forceful personality. Every single aspect of government policy bore the strong imprint of Mao's ideas and his personal brand of Communism.
Even after the disaster of the Great Leap Forward, when Mao's power seemed to be very much on the wane, he still retained enormous loyalty within both the governing Chinese Communist Party (CCP) and wider sections of Chinese society. Mao harnessed this fanatical loyalty, especially among the young, to launch the Cultural Revolution against the Party cadres and members of the government he believed were taking China down a capitalist road.
Though many present-day members of the Chinese political elite have openly criticized elements of Mao's legacy, his memory continues to be venerated by many in China. It is commemorated by countless busts, portraits, and statues. Despite the huge economic and social changes that China has undergone since Mao's death, Mao still retains his position as a secular icon. This demonstrates the immense significance of Mao to the nation he established. However far down the capitalist road the current leadership of the CCP may have gone, they ultimately derive their legitimacy not from the people (as China is a dictatorship, not a democracy), but from the man who established the state which they now govern.