Top officials of the world's most populous nation, including Xi himself, took part in a leadership vote at the Great Hall of the People in Beijing, taking turns to place red papers into ballot boxes, but the outcome was never in doubt.
"Now I announce comrade Xi Jinping is selected as president of the People's Republic of China," said Liu Yunshan, a top official of the ruling party who chaired the session at the National People's Congress, the rubber-stamp parliament.
To loud applause, Xi, 59, stood up and bowed to the delegates and the platform, before shaking hands with other officials and walking off the stage.
Li Yuanchao, a member of the Communist Party's Politburo but not of its top seven-member Standing Committee, and who is seen as having reformist leanings, was named as vice-president, a largely symbolic post.
Xi's government appointment was effectively guaranteed by his party position.
He formally takes the reins of the world's second-largest economy with Li Keqiang, who is due to be anointed as premier on Friday, marking the final step in the nation's once-in-a-decade power handover.
The party leadership is the real source of authority in China, but the title of head of state will increase Xi's public and international role.
Since he took the top Communist post in November, Xi has pledged to preserve the ruling party's supremacy, as well as improve livelihoods, implement economic reforms, and crack down on corruption, which incenses popular opinion.
In the months since Xi's promotion a parade of lower-level officials have been exposed for graft in efforts that have been lauded in state media as proof of a crackdown.
However, despite the promises on hot issues such as graft and environmental protection which could prove a threat to party rule, observers say that concrete reforms would be complex and will not be swiftly introduced.
Officially, Xi is being elected for a five-year term, but barring extraordinary events the 59-year-old will hold the position for a decade.
Xi has already become head of China's top military body, the Central Military Commission, unlike his predecessor Hu Jintao, who at the same stage in the previous transition in 2003 was still substantially overshadowed by Jiang Zemin.
"In recent memory there is no comparable figure who has such power in his hand (so quickly)," said Willy Lam, a politics expert at the Chinese University of Hong Kong.
Xi is the son of one of China's most esteemed generals and known as a "princeling", the name given to relations of China's first generation of Communist leaders, who grew up immersed in the ruling party's upper echelons.
But he has threatened to target not only lowly "flies" but also top-ranking "tigers" in corruption crackdowns, warning that graft could "kill the party".
An investigation by US news agency Bloomberg found that Xi's family had amassed hundreds of millions of dollars in assets, casting doubt on his ability to implement major reforms which might threaten their business interests. There was no accusation of wrongdoing on his part.