Iranian parliament speaker Mohammad Bagher Ghalibaf has emerged as the key negotiator and one of the most high-profile figures in the Islamic republic's leadership as it enters a new phase after the US-Israeli war.A pillar of the Iranian establishment for some three decades and one of its most prominent non-clerical figures, Ghalibaf, 64, had spearheaded the war effort and led the high-stakes negotiating process that culminated with an agreement announced Monday to halt the hostilities.Ghalibaf survived more than five weeks of US-Israeli attacks on Iran that killed supreme leader Ali Khamenei, top security official Ali Larijani and a host of other key figures.He came into public view for the first time in weeks in April to lead the Iranian delegation in talks in Islamabad with the United States, meeting Vice President JD Vance, the highest-level contact between the two foes since before the 1979 Islamic revolution.An image published on social media by Iranian embassies abroad put Ghalibaf centre stage in the Iranian negotiating team, looking animated and gesturing with his hand, as Foreign Minister Abbas Araghchi busied himself with teacups.The workings of the Iranian leadership without Khamenei, who dominated it for nearly four decades, remain unclear.Khamenei's son Mojtaba was named as his successor but has yet to appear publicly after he was reportedly wounded in an airstrike."Following Larijani's assassination, Ghalibaf has emerged as the new public face of the Islamic republic's war effort and diplomacy," said Farzan Sabet, a managing researcher at the Geneva Graduate Institute."But we shouldn't overstate the extent to which he's in the driver's seat: He still answers to higher powers in Tehran," he added.These include Mojtaba Khamenei and the Revolutionary Guards, the ideological arm of Iran's military, where Ghalibaf was a key figure as aerospace forces commander, Sabet said.- 'Professional bargainer' -While the trip to Islamabad was Ghalibaf's first appearance in public since before the war, he has kept a high profile online with almost daily social media posts, mixing commentary on recent developments and the negotiations with threats of harsh retaliation should the fighting resume.His posts on X in idiomatic American English have garnered wide attention and raised questions over who is actually writing them, given Ghalibaf is not known to be a fluent English speaker.