The World Trade Organization's first female and first African director-general Ngozi Okonjo-Iweala began work on Monday (March 1) - ending a six-month leadership void.
"I have a lot of work to do, so I feel ready to go."
The 66-year-old Nigerian was confirmed as boss last month, after a long campaign that was derailed in the latter stages by a Trump administration veto.
She pledged to "forget business as usual" at the WTO, which is struggling to strike new deals and whose arbitration functions are paralyzed.
The first day with the former finance and foreign minister at the helm coincides with a meeting of its top decision-making body, the General Council.
Its 164 member states will discuss topics including trade rules on COVID-19 vaccine distribution.
Okonjo-Iweala said she was particularly hopeful of clinching a deal on fisheries subsidies after 20 years of talks.
“It’s been 20 years and 20 years is enough. That’s my slogan. Now we have to get it done."
The director-general role does hold few executive powers though, and some analysts have questioned her ability to revive the body in the face of so many challenges - including persistent U.S.-China trade tensions and growing protectionism heightened by the global health crisis.