The swearing-in ceremony held in parliament saw Hipkins officially taking up the top job and Carmel Sepuloni becoming the deputy prime minister.
Prime Minister Hipkins will reshuffle the cabinet next week. Besides the top leadership role, Hipkins himself will be the minister of national security and intelligence.
Tackling inflation will be his priority, he said, as Stats NZ released on Wednesday the growth of New Zealand's consumers price index remained 7.2 percent in the 12 months to December 2022.
Announcing her resignation last Thursday, Ardern said, after five and a half years of the top leadership role, she could not keep going for another year or term after careful consideration.
"Being prime minister has been the greatest honor of my life," Ardern said, citing her cabinet's achievement in alleviating child poverty and increasing welfare support and public housing stock.