Uhuru was announced victor with 8, 203,290 (54.27%) votes by IEBC chairman Wafula Chebukati with his strongest contender Raila Odinga of NASA trailing him with 6, 762, 224 (44.74%) votes on Friday August 11, three days after the polls.
With reports of violence in Kisumu, Kenya's third city, there were fears that the former British colony could witness a reprise of the violence that claimed 1,300 lives after Odinga's defeat in another election ten years ago.
Earlier Friday, worldwide observers called upon candidates to respect the final outcome and resolve any poll disputes through legal avenues.
"To our brothers who were worthy competitors, we are not enemies".
At least five people have been killed in post-election violence in Kenya after opposition leader Raila Odinga claimed "massive" fraud in Tuesday's vote. But we have had concerns raised and we can't ignore those concerns.
Opposition candidate Raila Odinga, 72, has alleged that the results of Tuesday's balloting were rigged, and he pledged not to accept them unless he was declared the victor.
But Odinga supporters, said they are being robbed of yet another election.
As Kenyatta's supporters celebrated his victory in Nairobi, Odinga's supporters clashed with police, setting objects on fire to protest the result. "And then if they have a concern, go through the rule of law, go to the court process and let the evidence be there for everybody to see".More news: Giant inflatable Trump-like chicken graces the White House
In a statement issued Thursday, Mr. Obasanjo congratulated Kenyans for the relative peace that had attended the campaign and preparation for the elections.
Worldwide observers have praised the handling of the election, with the European Union saying it had seen no sign of manipulation despite opposition complaints and scattered protests.
He has urged the IEBC to conduct the tallying process in an effective and transparent manner within the legally stipulated timeframe and, where necessary, to engage in dialogue with political actors before the official announcement of results.
"The (hacking) claims being made could not be substantiated from our end", he said following an investigation.
Police were deployed Friday to opposition strongholds across Kenya in anticipation of protests following the proclamation of Kenyatta's victory and trouble broke out within minutes of the IEBC announcement. Any turmoil in East Africa's largest economy would be felt across the region, particularly in landlocked Uganda and Rwanda, which rely heavily on Kenya's ports and roads to access global markets. In the weeks that followed, members of Kibaki's Kikuyu ethnic group and Odinga's Luo group attacked, killed and raped one another and burned down houses. "Violence must never be an option", he said on Friday.
Kenyan election officials say only they have the authority to declare the victor, and global election observers say they have seen no signs of interfering with the vote.
Opposition politicians on Friday accused the observers of "rushing to judgment" and collusion with the government.
As well as a new president, Kenyans also elected new lawmakers and local representatives.