The president and his supporters have won almost all of the seats in Iran's key supervisory body. The Assembly of Experts chooses the next supreme leader: the ayatollah.
The government said on Monday that officials had finished counting the votes. "Participation in Tehran was 50 percent and the whole country was around 62 percent," Interior Minister Abdolreza Rahmani Fazli told reporters.
Rouhani and his close ally former President Akbar Hashemi Rafsanjani won 15 out of 16 seats in Tehran for the Assembly of Experts, state news agency IRNA said.
Ayatollah Ahmad Jannati was the only conservative hard-liner to make it to the council from Tehran. The cleric is also the chairman of the Guardian Council, which disqualified several reformist leaders from contesting Friday's polls.
Jannati is considered one of the strongest critics of Rouhani's reform program.
Rafsanjani was expected to take over as head of the 88-member body, which chooses the country's supreme leader. The post is currently held by Ayatollah Ali Khamenei.
The reformists also won all 30 seats representing Tehran in the 290-member parliament.
Moderates have also gained seats and could team up with Rouhani's supporters to outnumber conservatives opposed to Iran's nuclear concessions. Signed last year, that agreement helped end crippling sanctions against Iran and open its markets to foreign businesses.
Observers said the former president and Rouhani were likely to reduce the influence of conservatives in the council and in Iran's politics in general.
Iran's official broadcaster reported that the results heralded "the end of the presence of a powerful majority in the parliament that overshadowed [the] decision-making apparatus in the country over the past decade."
mg/kms (dpa, Reuters)