It was a merger of the cities of Manila and Quezon and the then-Rizal towns of Caloocan, Makati, Mandaluyong, Parañaque, Pasay, and San Juan.

Manila was divided into four districts: Quezon City was divided into two districts, bisected by the Manila Circumferential Road (now EDSA): Meanwhile, the city's present-day northern portion was then part of Caloocan and San Mateo, Rizal.

The Sakura Heiyei military reservation, located south of Maricaban Creek and including the Nichols Field (now part of Pasay), Fort McKinley (now Fort Bonifacio), along with the present-day eastern and southwestern portions of Parañaque, was not part of Greater Manila.

[3][7][8] The city was also represented in the National Assembly of the Japanese-sponsored Second Philippine Republic under the at-large district of Manila.

Jorge B. Vargas assumed the mayoralty post in December 1941 upon appointment by President Manuel L. Quezon.