He also noted that Ghana “made history” by electing its first female Vice President, Jane Naana Opoku Agyemang.
And he thanked Bawumia for conceding long before the official results were announced.
The vice president said he was doing so “to avoid further tensions and maintain peace in our country.”
Nevertheless, there was some disappointment in that it took too long to announce the official results.
President Nana Akufo-Addo is resigning after reaching the official term limit of two terms.
This election was held amidst the worst economic crisis in a generation.
Unemployment, cost of living and concerns about the environmental impact of illegal gold mining, known as ‘galmasi’, were key issues.
With many Ghanaians desperate for change, Mahama won several regions, including Bono, Ahafo, West and Central, which the ruling New Patriotic Party (NPP) won in 2020.
Mahama’s supporters have been celebrating across the country following Bawumia’s concession on Sunday.
People cheered, waved flags, blew horns and spun their motorcycles.
“I am so happy with this victory,” Salifu Abdul-Fatawu told the BBC in the central city of Kumasi.
He said this means jobs for him and his siblings and lower food and fuel prices.
