Weah had already conceded defeat on Friday evening, based on the results of more than 99.98 percent of the polling stations.
Joseph Boakai has been declared winner of Liberia’s presidential election.
He was declared winner on Monday, beating incumbent George Weah, the National Electoral Commission (NEC) said after completing the ballot count.
Boakai won with 50.64 percent of the vote, against 49.36 percent of the vote for former international football star Weah, Davidetta Browne Lansanah, president of the commission, told reporters.
Boakai won with only a 20,567-vote margin.
Weah had already conceded defeat on Friday evening, based on the results of more than 99.98 percent of the polling stations.
The outgoing president and former football star won praise from abroad on Monday for conceding and promoting a non-violent transition in a region marred by coups.
“Liberians have once again demonstrated that democracy is alive in the ECOWAS region and that change is possible through peaceful means,” the Economic Community of West African States said in a statement.