The 56-nation Commonwealth announced Ghana's foreign minister Shirley Ayorkor Botchwey as the new secretary general of the organisation as a rancorous summit concluded in Samoa on Saturday.
The voluntary association of sovereign states is mostly made up of former British colonies.
Botchwey was one of three candidates vying for the post, all who have backed calls for Britain to address the legacy of colonialism and slavery.
A former lawmaker, she has served as foreign minister for the past seven years, notably steering Ghana's two-year tenure on the UN Security Council, ending December 2023.
She has backed the drafting of a free trade agreement among Commonwealth member states and has previously said she stands for reparations.
"Financial reparations is good," she said at an event in London earlier this year.
A Commonwealth Secretary General can serve a maximum of two terms of four years each. The incumbent is Dominican Baroness Patricia Scotland.
By convention, the secretary general role is rotated around the body's four geographical blocs: the Pacific, Asia, Europe, and Africa. It was now Africa's turn.
"Truly humbled by the overwhelming support of the Commonwealth Heads of Government in selecting me as the incoming Secretary-General of the Commonwealth" she posted on social media.
"The work indeed lies ahead!"
The Commonwealth promotes democratic governance, cooperation in trade, education, climate advocacy and the transparency of financial systems.
It is headed by King Charles III, but the secretary general is responsible for running the London-based secretariat.
Botchwey's appointment was made at a summit in Samoa which had been expected to focus on climate change, but became mired in factious debate about reparations.
Many African, Caribbean and Pacific nations want to see Britain -- and other European powers -- pay financial compensation for slavery, or to at least make political amends.
They want UK leaders to commit to a discussion on reparatory justice -- which could involve financial payments.
But it is a debate Britain's cash-strapped government has worked hard to avoid.
The Bahamas' Prime Minister Philip Davis told AFP that a real discussion about the past was vital.
"The time has come to have a real dialogue about how we address these historical wrongs," he said.
"Reparatory justice is not an easy conversation, but it's an important one."
"The horrors of slavery left a deep, generational wound in our communities, and the fight for justice and reparatory justice is far from over".
Experts estimate that over four centuries about 10-15 million slaves were taken from Africa to the Americas.
The true figure, and human toll may never be known. The practice finally ended around 1870.
The British royal family, which benefited from the slave trade over centuries, has faced calls to apologise.
King Charles monarch stopped well short of that on Friday, asking summit delegates to "reject the language of division".
"I understand, from listening to people across the Commonwealth, how the most painful aspects of our past continue to resonate," he said.
"None of us can change the past. But we can commit, with all our hearts, to learning its lessons and to finding creative ways to right inequalities that endure."
