[6] Dadu's diplomatic tour of duty spans over two decades, during which he held several positions in foreign relations, policy management, and international cooperation.

In this role, he managed diplomatic relations between Nigeria and Eastern European countries, handling policy matters and coordinating bilateral meetings.

By January 2003, he was appointed Desk Officer for Western Europe and Commonwealth Affairs at the Ministry, overseeing diplomatic engagements and policy matters related to these regions.

His tenure in Paris involved facilitating visa issuance, providing consular services, and representing Nigeria in diplomatic engagements with the French government.

In October 2018, Dadu was posted to the Nigerian Embassy in Mexico City, where he served as Minister in charge of Administration, Political, and Economic Affairs.

His PhD dissertation focused on "Regional Cooperation for the Control of Illicit Proliferation of Small Arms and Light Weapons: The Case of ECOWAS."

In 2015, he was a major contributor to a book on the UN Program of Action to combat the illicit trade of small arms titled, Anatomy of a Consensus (edited by Joy Ogwu) where he wrote extensively on "Implementing the Decisions of the 2nd Review Conference (2012) of the UN Programme of Action (PoA) to Prevent, Combat and Eradicate the Illicit Trade in Small Arms and Light Weapons in all its Aspects at the Regional Level: The Case of ECOWAS.