Mr Weah, in a Twitter post after the results were announced, said: "My fellow Liberians, I deeply feel the emotion of all the nation".
"The Nigerian leader also commends outgoing President Ellen Johnson Sirleaf, under whose 12-year watch Liberia had transformed from being a pariah state to a country doing remarkably well on many fronts such as, women and civil rights issue, peace building and consolidation, ECOWAS and the Mano River Union".
With this, Weah will serve as the 25th president of Liberia with effect from the third working Monday of January.
"Success for George Weah is victory for the whole country", a 47-year-old engineer named Randall Zarkpah said as he walked home with his young son through streets filled with the sounds of auto horns and loud cheers as dusk fell.
A falling out with Boakai's supporters, which saw Johnson Sirleaf's own Unity Party accuse her of interfering in the first round of the election - charges she denied - has also left lingering bad feelings.
French President Emmanuel Macron hailed the ex-star striker's victory in a tweet on Friday.
"And in everything that we do and say, let us always think Liberia, love Liberia, and build Liberia", he added.
He is set to succeed Sirleaf, Africa's first elected female president, in what will be Liberia's first democratic handover in decades. He played for AC Milan, Paris St Germain and Chelsea.
"The President equally applauds the efforts of the National Election Commission of Liberia, as well as regional and global observers who have contributed immensely to the electoral process and the strengthening of post-conflict democracy in the West African country".
Chairman of the commission, Mr Jerome Korkoya, made the declaration after announcing the final results of the December 26 presidential runoff election at the NEC headquarters in Monrovia.
Just like every African legend, Drogba took to social media to congratulate the 1995 Fifa World Player of the Year on his victory at the polls on Wednesday.
In the country's first democratic transition in more than 70 years - with 98.1 per cent of the vote counted - Mr Weah led with 61.5 per cent to Vice-President Joseph Boakai's 38.5 per cent, National Elections Commission chairman Jerome Korkoyah said on Thursday. She led the country from back-to-back civil wars and saw it through a deadly Ebola outbreak that killed almost 5,000 Liberians.
The 51-year-old Weah, a senator who entered politics after his 2002 retirement, led the first-round election in October but didn't receive enough votes to win outright.