He is part of the ruling family in Abu Dhabi, brother of UAE President Mohamed bin Zayed Al Nahyan.

Tahnoun has been involved in numerous controversies, from violating EU sanctions against Syrian president Bashar al-Assad, spying on political opponents in Project Raven, deals to re-sell Russia's Sputnik vaccine to poor countries at substantial mark-ups, orchestrating the Qatargate bribery case, and a smear campaign against Qatar and the Muslim Brotherhood, as revealed 2023 in the Abu Dhabi Secrets.

In March 2013 President Sheikh Khalifa bin Zayed Al Nahyan appointed him as a deputy national security advisor.

According to financial records reviewed by The Wall Street Journal, Sheikh Tahnoun deposited about $200,000 into the bank accounts held by the niece of Syrian President Assad, Aniseh Shawkat, over a period of several years as her sponsor.

[18] Multiple ex-CIA officials told Reuters that the agency does not gather "human intelligence" from the UAE informant because it shares common enemies with the United States.

Retired CIA official "Norman Roule" defended the US for not spying on the Emirates, stating that the actions committed by Abu Dhabi have "contributed to the war on terror, particularly against al-Queda [Qaeda] in Yemen.

[22][23] The Italian news site Dagospia alleged that it was Tahnoun who executed the scandal against Qatar and provided tips to Belgium, which opened the investigation.

[25] A unit of Sheikh Tahnoun’s IHC, International Resources Holding (IRH) acquired Zambia’s Mopani copper mine under its chief global strategist, Sibtein Alibhai.

The United Nations investigators alleged that Alibhai and IRH approached and had meetings with several gold smugglers from Democratic Republic of Congo.