Originally, it would have been Xi's second and final term as head of state, but last week, the National People's Congress (NPC) approved a controversial proposal to abolish term limits, in effect allowing Xi to continue for as many terms as he likes.
Al Jazeera's Scott Heidler reports from Beijing, China.
While most of Xi's power flows from his roles as party chief and supreme military commander, being president - or "chairman" in Chinese - gives him legal standing as head of state.
Wang was at the frontline of Xi's anti-corruption crusade, heading the party's Central Commission for Discipline Inspection, which has punished 1.5 million officials in the past five years, from low-level cadres to regional leaders and generals.
Yanmei Xie, a China policy analyst for Gavekal Dragonomics in Beijing, said appointing Wang could extend decision-making beyond the seven-member Politburo Standing Committee, the party's top body and a key component of the collective leadership system set up after Mao's tumultuous rule.
Wang's appointment is crucial for "rising China" as he can help Xi deal with increasingly frayed relations with the Trump-led United States amid fears of a trade war.
The ceremony - which took place after Xi received unanimous support from lawmakers to serve a second term as president - was a symbolic move to show the significance of the constitution, which was revised last week to include Xi's political theory, "Xi Jinping Thought".
Xi and Wang spoke only to pledge allegiance to the constitution, with Wang giving the podium an emphatic tap after he finished.
"Xi is already a very powerful man".
China's capital was engulfed in a rare flurry of swirling snow on Saturday, sending delegates of the congress scurrying from the Great Hall of the People after the vote.
"Wang's crackdown is unlikely to be forgotten within the party establishment".
The vice-president position has been a largely symbolic role in past decades, but that will not satisfy Wang, who is widely respected for his decisiveness and efficiency, the daily said.
"This is a great happiness for the country and the nation".
Ravens sign WR Michael Crabtree to three-year deal
The 6-1, 215-pounder has totaled at least 85 catches in a season three times, with a career-high 89 during the 2016 campaign. The Ravens are looking to improve their receivers for quarterback Joe Flacco after ranking No. 29 in passing last season.
Gattuso refuses to blame defeat on Welbeck dive
The Gunners went into the game with a healthy 2-0 advantage following an impressive win at the San Siro a week ago. However, Danny Welbeck's controversial penalty got the Gunners back on level terms.
Cyber Monday 2017 – The top sellers in electronics this year
Apple’s 9.7-inch Wi-Fi enabled iPad Pro was also still a great seller thanks to massive price discounts from retailers. Microsoft dropped their game changing console update, the Microsoft Xbox One X with a 1TB hard drive and 4K compatibility.