Published: 2021-04-05 15:54:34 BdST
Chinh, 62, was the sole nominee put forward by the ruling Communist Party for the post at a congress earlier this year. He won 96.25% of the vote at an official National Assembly vote on Monday.
He was formerly head of the Party's powerful and influential Central Organisation Commission which has long reach across Party ranks.
He will replace former Prime Minister Nguyen Xuan Phuc, who was confirmed earlier on Monday as the country's new president, a predominantly ceremonial role.
Chinh was previously party chief of the northern province of Quang Ninh and deputy head of the Ministry of Public Security, the country's powerful internal security agency.
He will be the first Vietnamese prime minister not to have previously served as a deputy prime minister since the launch of Vietnam's progressive "Doi Moi" reforms.
Vietnam has no paramount ruler and is officially led by four "pillars": the powerful General Secretary of the Communist Party, a state president, a governing prime minister and the chair of the National Assembly, a largely rubber-stamp legislature.
The main candidates for each post had all been widely known in Hanoi's political circles, but were officially declared top secret in December last year in order to discourage potentially critical debate.
The Party retains tight control of media and tolerates little criticism.