Touadera, a former academic who pledged to end corruption and bring unity to the war-ravaged country, won 62.71 percent of votes in the presidential runoff election, according to the National Elections Authority, which released provisional results Saturday.
His rival, Anicet-Georges Dologuele, also a former prime minister, took 37.29 percent.
The runoff vote was held on February 14
after no candidate won a majority in the first round in December.
Touadera came second in the first round of voting.
The country's interim president Catherine Samba-Panza could not run, as members of the country's transitional government were prohibited under the constitution from participating in the election.
The final results are expected to be validated by the country's Constitutional Court within a week.
The Special Representative of the U.N. Secretary-General in the country, Parfait Onanga-Anyanga, praised the "the high level of patriotism and maturity demonstrated by the presidential candidates" and called on both camps to "to preserve the spirit of peace that has prevailed thus far."
Onanga-Anyanga called the election a historic moment for the war-torn nation and reiterated the international community's support in its walk towards lasting peace.
Challenges for new leader
Touadera faces a tough road ahead, as years of deadly violence between Muslims and Christians have left the country in a dire condition.
He served as prime minister for five years from 2008 to 2013 under former President Francois Bozize, and some see his ties to the former leader as controversial.
Bozize, who took power in 2003, is accused of human rights violations and is the subject of an international arrest warrant.
In 2013, his government was toppled by Muslim Seleka rebels, who installed their leader.
That prompted reprisal attacks by Christian fighters, resulting in numerous civilian deaths.
Sectarian tensions between Muslims and Christians have continued since.
Nearly a million people have been displaced by the fighting and about half of the country's population has limited or no access to food.
Children have also been dragged into the war, with as many as 10,000 recruited by armed groups during the crisis.