There were still some problems with the vote, he said: delays, some agents being denied entry to polling stations, names missing from the register, and the failure of some electronic voter identification devices.
But as the use of so many devices outside the phone networks meant this could be delayed, the potential to cheat remained.
That explosive episode would come to influence every subsequent Kenyan election.
On Monday he called on his followers to rally in Nairobi's central park to await the results.
By the end of voting, there were no significant reports of irregularities. Running the poll costs some 49bn Kenyan shillings (about $480m); campaign spending may cost as much again, making Kenya's election more expensive per person than America's.
"Let God prevail. Let God govern the country", she said.
Kiingati said she voted for Kenyatta, who seeks a second term and faces a fierce challenge from opposition leader Raila Odinga.
President Barack Obama speaks during a news conference with Kenyan President Uhuru Kenyatta at the State House in Nairobi, Kenya, July 25, 2015.
The ruling Jubilee party also raised some problems but said it was largely satisfied.
"Peace. Peace. Peace. I say peace because Kenya was here before and it will be here after today", said the President.
The men belong to two of Kenya's main ethnic groups, Kenyatta from the Kikuyu, the largest, and Odinga from the Luo.
"The system is different from the 2007 and the 2013 system". The closest he got was prime minister, after the 2007 elections results were disputed to such an extent that it brought the country to the brink of a civil war. Even though the country has tried to implement programs to foster cohesion and reconciliation, Kenya's politics remain fractured along ethnic lines. More than 1,000 people were killed and hundreds of thousands were driven from their homes. Election procedures and security are thought to have improved since 2007.
If no victor is declared, the election will go to a runoff, which would be a first in Kenya's history. He has promised to fight corruption, create jobs for young people and set up programs to improve food security. Mr Odinga is unlikely have another chance at the presidency.
As he voted, Kenyatta said he would be willing to step down if he lost and called on Odinga to do the same.
"The question is not whether or not they will accept the result but what they will do when they don't accept it", he told Agence France-Presse.
The final week of campaigning has been marred by the murder of a top election official and claims of vote-rigging.
Some of the voters were at the polling stations as early as midnight in order to vote early at 6am local time when the polls opened.
Reaction to the result could partly depend on the performance of Kenya's electoral commission, which will collect vote counts from more than 40,000 polling stations.
Then an American and a Canadian working with NASA on their poll strategy were detained before being deported.
As president, Obama made a high-profile visit to Kenya in 2015, where he was celebrated as the country's most famous son.
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