On enshrining Xi's "Thought on Socialism with Chinese Characteristics for a New Era" into the Constitution, Shen said its inclusion into China's fundamental law "reflects the common aspiration of the entire Party and all Chinese people of various ethnic groups,".
Xi signaled his strength previous year when he had his theories added to the Communist Party charter and he bucked the trend to designate a successor at the end of his first term.
Such a revision "is conducive to maintaining the authority and centralised leadership of the party Central Committee with Comrade Xi Jinping as the core" and to "the long-term stability of the party and country", he said.
The main, no doubt, is elimination of limits to presidential errands that Deng Xiaoping had introduced in his day to institutionalize power and avoid Mao's personalism.
China's National People's Congress (NPC), the national legislature, adopted an amendment to the country's Constitution on Sunday.
When China's ruling Communist Party proposed the amendment in February, it was met with criticism from various quarters.
Xi's current term ends in 2023, but analysts say he is likely to continue as the country's leader.
Xi, who succeeded Hu Jintao in 2012 as General Secretary of the Communist Party, became China's President a year later.
The surprise move is the boldest yet by Jinping as he seeks to restore China to what he considers its rightful place as a global power - an agenda that his allies have suggested requires his leadership. Two delegates voted against the change and three abstained, out of 2,964 votes.
At the time, Xi vowed to root out corruption following a $10 billion smuggling scandal, but ruled out political reform to confront the problem, saying he would work within the one-party structure and system of political consultation and "supervision by the masses".
On Sunday, in a sign of the vote's sensitivity, government censors were said to be aggressively scrubbing social media of opposition to the historic move. A number of prominent Chinese figures have publicly protested the move, despite the risk of official retaliation. Leading Chinese officials have meanwhile repeatedly rejected any chance of adopting Western-style separation of powers or multiparty democracy.
Nevertheless, Xi's confident, populist leadership style and tough attitude toward corruption have won him significant popular support. In a news conference after the amendment was approved, a government spokesperson said that concerns about a power struggle like that seen during China's Cultural Revolution were "invalid", in response to questioning by a foreign reporter. He added, however, that he was concerned that the public discourse lacked a space for dissenting voices.