Iranian state television has described Zam as the "leader of the riots" that swept across the country around the turn of the year 2017-2018.
The protests that took place in about 70 cities were initially aimed at the tough economic situation in the country.
However, they later developed in a more political direction and turned against the Islamist regime and its spiritual leader Ali Khamenei.
Lived in exile
Ruhollah Zam lived and worked in Paris, according to Iranian authorities under the auspices of the French government.
But a little over a year ago, he was tricked into traveling to Iraq, where he was arrested by Iranian agents and then taken to his home country, writes AP.
He was sentenced to death in June, accused of the sweeping crime classification "mofsed-e-filarz", which can roughly be translated as "spreading corruption on earth".
Zam ran the news site AhmadNews and a channel on Telegram in which he published compromising information about people in the Iranian leadership.
He also spread videos that directly criticized the country's president Hassan Rouhani and Ayatollah Ali Khamenei.
Executed by hanging
Ruhollah Zam was executed by hanging on Saturday, which provoked strong reactions in the outside world.
France has previously described the death sentence as "a serious blow to Iran's freedom of expression and the press".
Reporters Without Borders calls the death penalty "a new crime by the Iranian judiciary"
Diana Eltahawy, regional director for the Middle East and North Africa at Amnesty International, described the execution as "a deadly blow to freedom of expression in Iran, which shows the authorities' brutal tactics to spread fear and deter political opposition"