The National Assembly of the Commonwealth was created under the 1935 Constitution, which served as the Philippines' fundamental law to prepare it for its independence from the United States of America.

In an attempt to win the loyalty of Filipinos, the Japanese established a nominally independent Republic of the Philippines, with a National Assembly as its legislative body.

The Jones Law provided for a Senate and a House of Representatives, whose membership were elected except for a few, which were appointed by the U.S. Governor-General without the need for confirmation.

The National Assembly first met officially on November 25, ten days after the Commonwealth government was inaugurated and elected Gil M. Montilla of Negros Occidental as its Speaker.

Commonwealth President Manuel L. Quezon, who had practical control of the National Assembly, addressed the body on its inaugural session and laid-out his administration's priorities and legislative agenda.

He was able to secure the passage of important legislation without much opposition, after he diluted the powers of the Speaker to a mere presiding officer.

Several economic measures were also tackled, including the impending difficulties on the phase out of free trade between the Philippines and the United States after independence, setting a minimum wage, and the imposition of new taxes among others.

[8] The second elections for the National Assembly were held on November 8, 1938, under a new law that allowed block voting,[9] which favored the governing Nacionalista Party.

[14] It furthered the emergency powers already granted to the President, such as the transfer of the seat of government and the extension of the effectivity of lapsing laws.

It utilized the existing administrative structure already in place and coerced high-ranking Commonwealth officials left behind to form a government.

[16] In order to win greater support for Japan and its war effort, no less than Japanese Prime Minister Hideki Tōjō promised the Filipinos independence earlier than the Tydings–McDuffie Act had scheduled.

[18] Though created subordinate to the executive, the National Assembly had the power to elect the President, who in turn appoints the provincial governors and city mayors, ensuring him control of the legislature.

Laurel called the National Assembly into a special session from October 17 to 23, when it passed resolutions expressing gratitude to the Japanese for its grant of independence.

Since the Philippines now acted as an independent state, the National Assembly created the Ministry of Foreign Affairs and a Central Bank.

It was scheduled to meet for its second regular session on October 20, 1944, but American forces had already begun their campaign to liberate the Philippines from Japan with its first attack on Manila on September 21, 1944.

[21] Meanwhile, all the laws passed by the Second Republic's National Assembly were invalidated by a proclamation of Gen. Douglas MacArthur on October 23, 1944[22] just right after reestablishing the Commonwealth government in Tacloban.