Masoud Pezeshkian received his certificate of appointment on Sunday after being elected as Iran’s new president.
He received the certificate and blessing from the country’s Supreme Leader Ayatollah Ali Khamenei, and was thus proclaimed the ninth President of the Islamic Republic.
The ceremony at the Khomeini Mosque in the capital Tehran was attended by the country’s political elite and numerous foreign diplomats.
Pezeshkian will be officially sworn in in parliament on Tuesday, when he will also introduce his vice presidents and cabinet members.
Pezeshkian, who is considered a moderate, won the second round of the presidential election against hardliner Said Jalili in early July.
However, according to the Iranian constitution, Khamenei is the political and religious head of state and has the final say in all strategic matters.
The snap elections were called after former incumbent politician Ebrahim Raisi died in a helicopter crash in May.
Pezeshkian, a 69-year-old heart surgeon and former member of parliament, is seen as loyal to the system, but he promised reforms in domestic and foreign policy during the election campaign.
“We have awakened new hope in the people, which we must not turn into new despair,” said the new president.