The leader of the operation was Kermit Roosevelt (1916-2000), a senior CIA agent, and grandson of the former President of the United States Theodore Roosevelt.
He convinced Shah Mohammad Reza Pahlavi to depose Mossadeq. Shah, who had previously been the only political figure in Iran who out-ranked the Prime Minister, tried to do it. But Mossadeq Rejected the Shah’s order and Shah had to leave Iran for Italy temporally.
The agents of Operation Ajax thus involved returning the Shah back to power in Iran, and convincing him to fire Mossadeq.
Approved in late June, 1953, the Shah returned to Tehran and fired Mossadeq on 22 August.