Buhari, candidate of Nigeria's opposition All Progressives Congress, was officially declared president-elect on Wednesday, the first time in Nigeria's history that a sitting president has been defeated at the polls.
Extending congratulations to the Nigerian people and Buhari, Obama said he looked forward to continuing to work with the newly elected government on shared priorities.
Jonathan, who promised free and fair elections in Nigeria, conceded defeat earlier Wednesday, a move praised by Obama as placing the "country's interest first."
Obama also urged Buhari and Jonathan to repeat their calls to their supporters to continue to respect the election outcomes, focus on unifying the country, and together lead Nigeria through a peaceful transition.