Ebrahim Raisi, a hard-line cleric close to Iranian Supreme Leader Ayatollah Ali Khamenei, on April 14 filed to run in the May presidential election.
Raisi, 56, a professor of Islamic law, is viewed as incumbent President Hassan Rohani's main rival for the presidency. Rohani, a politically moderate cleric, also filed for reelection earlier on April 14.
While Rohani has won praise for his groundbreaking nuclear deal with world powers last year, the pact's failure so far to stimulate strong economic growth and discontent due to high unemployment has created an opening for his opponents.
Raisi is expected to draw support from Iran's hard-line factions, including the powerful Islamic Revolutionary Guards Corps.
On April 14, he made it clear he would try to exploit economic discontent.
"Despite all the efforts of previous governments, the situation of the country is such that people ask why is there so much unemployment?" he said. Unemployment in Iran is around 12 percent.
Raisi reached out to moderates as well as hard-liners.
"I will be the candidate for the whole of Iran. I don't limit myself to a certain group, party, or faction," he said.
Raisi said he would announce detailed economic plans soon.
A potential spoiler for Raisi arose on April 12, when former hard-line president Mahmud Ahmadinejad made a surprise move to register for the election against Khamenei's advice.
A clearer picture will emerge next week when the conservative-controlled Guardians Council announces which of the nearly 1,000 registered candidates are allowed to run in the May 19 election.
Raisi has solid conservative credentials. Born into a religious family in the holy city of Mashhad, he is a "seyed" whose genealogy is said to lead back to the Prophet Muhammad.
Raisi has served in the country's judiciary for decades. He is also a member of the Assembly of Experts, an all-cleric body that will rule on Khamenei's succession.
Last year, Khamenei made Raisi head of the powerful Imam Reza charity foundation, which oversees the Imam Reza Shrine and owns a large business conglomerate.
With reporting by AP and AFP