Following the death of Ayatollah Khamenei in an attack, Ali Larijani was regarded as the de facto leader of Iran. Iran has confirmed that Larijani, the Secretary of the Supreme National Security Council, was killed in an Israeli strike. His death is expected to have significant repercussions on Iranian politics and the ongoing conflict involving the United States, Israel, and Iran.

Larijani was closely associated with the late former Supreme Leader Khamenei. After Khamenei's death, he emerged as Iran's acting leader and directed military operations against Israel and other nations in the region. Following the coalition airstrikes by the U.S. and Israel that resulted in Khamenei's death, Larijani delivered a forceful speech on national television, warning that Iran would make its enemies regret their actions and vowing a powerful response.

Larijani's killing in the Israeli airstrike represents another severe blow to Tehran's leadership. An expert commented that following Larijani's death, the Iranian regime may adopt a more hardline stance. Sina Azodi, Director of the Middle East Studies Program at George Washington University, stated, "Larijani's death will lead to a hardening of the regime." Azodi noted that Larijani maintained close ties with both political and military figures in Iran. "He had strong connections with various groups—including members of the Islamic Revolutionary Guard Corps and moderates—and used these relationships to influence military operations and communicate Iran's intentions externally." Azodi warned that Larijani's death could pave the way for the rise of more "hardline" figures, making it "more difficult to establish pathways to end the war."

In August 2025, Larijani was appointed Secretary of Iran's Supreme National Security Council by President Pezeshkian and served as the representative of the late Supreme Leader Khamenei on the council. Iranian media also referred to him as an adviser to Khamenei. He previously served as Speaker of the Iranian Parliament for 12 years, from May 2008 to May 2020. Although he led the principlist faction in parliament from 2008 to 2012, in recent years he has been described as a "moderate conservative." Before his role as Speaker, Larijani served as Iran's chief nuclear negotiator from 2005 to 2007.

His brother, Sadeq Larijani, is another prominent figure in the Islamic Republic, serving as Chairman of the Expediency Discernment Council, Iran's highest arbitration body responsible for making final rulings between the Parliament and the Guardian Council.

It is reported that after Khamenei was assassinated on February 28, Israeli forces tracked Larijani for several weeks. The Israeli military launched an airstrike in the early hours of March 17 targeting a location in Tehran, Iran's capital. Israeli Prime Minister Benjamin Netanyahu announced on March 17 that Larijani had been killed. On March 18, Iranian President Pezeshkian issued an official statement mourning the loss of Larijani, who died in what he described as a recent terrorist attack. According to Iranian sources, Larijani and his son Morteza Larijani were killed in an attack at his daughter's home in Pardis.