Quintana will fill out the unexpired term of Cory Booker, who was elected to the U.S. Senate last month and was sworn in Thursday.
Quintana is now the first Latino mayor in the city's 300-year history. Newark's next mayoral election takes place in May.
On Monday morning, Newark's city council unanimously chose Quintana to serve as mayor and he took the oath of office in council chambers.
He automatically became acting mayor when Booker's resignation took effect, but now that designation has been removed.
The 53-year-old Quintana is a native of Puerto Rico who moved to Newark with his family at age eight. He had served on the city council since 1994.