For several years, the 62-year-old has had his base in Qatar. From there, he has, as chairman, led the movement's highest decision-making body, the so-called politburo with 15 members, and has become a face internationally.
Haniya was born in an established refugee camp on the Gaza Strip, near Gaza City. He joined Hamas in the late 1980s and was close to Hamas founder and first leader Ahmed Yassin.
He is said to have been killed during a visit to Iran's capital when the country's new president Masoud Pezeshkian was sworn in on Tuesday.
Sons killed
Haniya was appointed the movement's highest political leader in 2017, and was previously prime minister in a Palestinian co-government before Hamas forcibly drove rival Fatah from the Gaza Strip (2006).
In April, three of Haniya's sons and several of his grandchildren were killed in an Israeli air raid in Gaza, according to Hamas. He himself insisted that the death of his family members would not affect the negotiations on a ceasefire between Hamas and Israel.
Haniya has, during the war, after Hamas' terrorist attack on October 7, traveled on a mission to both Iran and Turkey and met with both the Turkish and Iranian presidents. He is said to have maintained good relations with the leaders of the various Palestinian factions, including rivals to Hamas.
Negotiations
By Haniya's side in Qatar was also the long-time leader figure Khaled Mashal, who has been a member of the politburo all along.
The Qatari leaders' approach to negotiations on a ceasefire is reported to differ from that of the Gaza leaders. And it is the latter who hold the hostages being negotiated about.
Hamas' highest leader on site in Gaza is Yahya Sinwar, 61. He is sometimes pointed out as the movement's de facto highest leader and is considered a particularly tough one. Today, Sinwar is believed to be hiding somewhere in Gaza's underground tunnel network.
