In an official statement on Monday, the former Majlis Speaker said he would continue to help the Principlist camp win the election regardless of his withdrawal.
Haddad-Adel said he stepped aside after evaluating the situation and the realities on the ground.
The sitting lawmaker expressed hope that his decision would help Principlists win the race in the first round or in a possible runoff.
Haddad-Adel also called on the Iranian nation to take part in the elections en masse.
The seven candidates in the race include President of the Expediency Council’s Center for Strategic Research Hassan Rohani, Secretary of the Supreme National Security Council Saeed Jalili, Secretary of the Expediency Council Mohsen Rezaei, Tehran Mayor Mohammad-Baqer Qalibaf, former Foreign Minister Ali Akbar Velayati, former First Vice President Mohammad-Reza Aref, and former Telecommunications Minister Mohammad Gharazi.
The president of Iran is elected for a four-year term in a national election. This year’s election will be held on June 14.
Nearly 50.5 million Iranians are eligible to vote in the upcoming presidential election.