In the legislative polls later that year, Fuentebella won a seat in the unicameral National Assembly and served two terms until 1941.

Although the Senate was restored in 1941, Fuentebella ran for a seat in the Lower House in the November polls.

During the Japanese Occupation, from September 1943 to December 1944, Fuentebella was appointed Commissioner of the 5th Military District comprising the entire Bicol Region.

After consulting guerilla leaders, he accepted the appointment from the Laurel government reluctantly and only to prevent more Japanese atrocities.

Subsequently, Philippine President Ferdinand E. Marcos appointed him Presidential Adviser on Foreign Affairs.

One of his greatest achievements as a politician was the extension of the Philippine National Railways to Bicol, establishing Camarines Sur Polytechnic Colleges in Naga City, and being the author of the "Flag Law".