Xi Jinping was also elected as chairman of the Central Military Commission (CMC), reports Xinhua news agency.
Nearly 3,000 members of the (NPC) voted unanimously at the Great Hall of the People in Beijing for Xi to be President in an election where there was no other candidate.
Since Mao Zedong, leaders in China had been limited to two terms in office.
When Xi had this restriction changed in 2018, it transformed him into a figure with a reach not seen since Chairman Mao, reports the BBC.
The vote on Friday was largely ceremonial as he had already locked in a historic third term as head of the Chinese Communist Party at a major party congress last October.
Changes to the country's leadership take place every five years and usually closely mirror the reshuffle announced at the party congress.
Meanwhile, naming of a new premier and various ministers in the coming days is considered more important, reports the BBC.
The new appointees are all expected to be Xi loyalists, including Li Qiang, who is tipped to serve as the President's number two.
Xi has solidified his rule as China reopens from his bruising zero-Covid policy that has fuelled anti-government protests.
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