Li, 57, currently the Vice Premier was nominated for the top post by the newly elected President Xi Jinping and his candidature was endorsed by the 3,000-member Parliament, the National People's Congress (NPC).
Li was named as the new Premier, a day after China's Parliament formally elected Xi, as President, four months after he took charge of the Communist Party.
Besides being the General Secretary of the Communist Party of China (CPC), which effectively rules the country, Xi was also appointed as the Chairman of the powerful Military Commission, when he was elected as the new leader of the party in November last year.
A princeling himself like Xi, Li, born into the family of a local official in Dingyuan County, reportedly refused his father's proposition to be groomed to be the leader of the local county.
During the Cultural Revolution headed by Mao Zedong he was sent to the rural labour camp in Fengyang County, Anhui, where he eventually joined the Communist Party.
He acquired Doctorate degree in Economics and became the Communist Youth League Secretary at Peking University in 1980. Li later acquired a law degree.
Li climbed the ranks while working closely with outgoing President Hu Jintao in his early days while working in the Youth League.
Known to be easy going, like his predecessor Wen, Li has the reputation for caring the less privileged.
Li's period in the rural areas was marked by some setbacks specially the spread of HIV through contaminated blood. But he retrieved his image by doing a better job reviving economy of Henan province, with a string of reforms in state-owned industries.
Besides Li, the NPC has elected a new set of Ministers and officials for the top military posts, completing the once-in-a-decade leadership change of the ruling Communist Party of China.