[13] During the Estrada administration, Diokno initiated and instituted several reforms that would enhance transparency and improve the efficiency of the delivery of government services.

This allowed agency heads to immediately plan and contract out projects by just looking at the GAA, which is available in print and at the DBM website, without waiting for the issuance of an allotment authority.

[14] Diokno initiated the reform of the government procurement system (GPS) through the adoption of rapidly improving information and communications technology.

[15] Other budget reforms instituted by Diokno concerned procedures for payment of accounts payable and terminal leave/ retirement gratuity benefits.

The release of cash allocation were programmed and uploaded to the department's website while payments were made direct to the bank accounts of specific contractor.

[14] In his third tour of duty as Budget Secretary, Diokno intended to pursue an expansionary fiscal policy to finance investments in human capital development and public infrastructure.

On March 4, 2019, President Duterte appointed Diokno as the fifth Governor of the Bangko Sentral ng Pilipinas (BSP), of which he will finish the unexpired term of his late predecessor, Nestor Espenilla Jr. which was supposed to end in July 2023.

[19][3] On January 12, 2024, President Marcos subsequently appointed Diokno as one of the six members of the Monetary Board of the Bangko Sentral ng Pilipinas, replacing Peter B. Favila in the position.