Confined to a wheelchair since his teens when he lost the use of his legs in an accident while playing football in Gaza's Shati refugee camp, Yasin's emblematic image is ubiquitous throughout the Gaza Strip, and adorns the prison cells of many resistance fighters held by Israel.
He had frequently said Hamas would only stop its bombing campaign if the Israeli army stopped "killing Palestinian women, children and innocent civilians".
Expelled from home
The diminutive and bearded Yasin, who was always seen wearing the traditional white skullcap, founded the movement at the start of the first Palestinian Intifada, or uprising (1987-1993) when he was a Gaza-based leader of the Muslim Brotherhood, a religious and political organisation founded in Egypt in the 1920s, with wide support across the Arab world.
Owner of a distinctive high-pitched voice, Yasin needed help in all daily activities and suffered from muscular deterioration, chronic breathing problems and hearing loss.
"The Jewish people have drunk from the glass of suffering and lived dispersed around the world. Today this people wants to force the Palestinian people to drink from the same glass"
Shaik Ahmad Yasin,
Hamas founder and spiritual leader
Father to 11 children, the elderly shaikh belongs to one of many Palestinian families expelled from their homes in what is today Israel during the first Israeli-Arab war in 1948.
Shaikh Yasin was born in 1936 in Majdal near the coastal town of Askalan, but fled to Gaza with his family after the village was destroyed in 1948.
Despite his paralysis, after completing secondary school Yasin left for Cairo, where he spent a year studying at Ain Shams University.
A lack of money forced him to cut short his studies and return home, but his year in Cairo was to prove decisive since it was there that he became involved with the Muslim Brotherhood.
Encouraged by Israel
Back in Gaza, Yasin founded his own movement, al-Mujama al-Islami, in the 1970s and began recruiting young activists.
At the time, Israel tacitly encouraged the growth of Islamist opposition groups in Gaza as a counterweight to the secular militancy of Yasir Arafat's revolutionary Fatah movement.
Hamas was allowed to open mosques, hospitals, and libraries among other philanthropic work. The movement was used by the Israelis to discredit Arafat’s leadership which was in exile in Tunisia at the time.
Caught up in the fervour of the 1979 Iranian revolution, Yasin set up a more radical movement - Majd al-Mujahidin.
He was arrested a first time in 1984 for illegal possession of weapons and explosives, but released a year later after which he set to work creating Hamas, an acronym for the Islamic Resistance Movement.
Since its inception in December 1987, Hamas has carried out the majority of attacks against Israeli targets, and become the Zionist state's most formidable enemy.
Palestinian boys pray in front of Hamas graffiti in Gaza city
Hamas does not regard its struggle as “one of borders” because according to the group, “the Jews have no place in Palestine”.
It does not recognise Israel’s right to exist and its long-term aim is to establish an Islamic state on pre-1948 borders.
But it has set its goal, at least for now, on a complete Israeli pullout from territories occupied during the 1967 Arab-Israeli War – the West Bank, East Jerusalem and the Gaza Strip.
Recently it had expressed a willingness to suspend resistance if Israel pulled out of the West Bank and Gaza and allowed the Palestinians their own state in the illegally occupied territories.
The glass of suffering
Hamas has been a staunch opponent of the 1993 Oslo peace accords between Israel and the Palestinians – an agreement which recognised Israel’s existence and paved the way for Arafat’s return from exile to oversee Palestinian self-rule in areas of the West Bank and Gaza Strip.
Arrested again in 1989, Yasin listened impassively as an Israeli court sentenced him to life in prison.
"The Jewish people have drunk from the glass of suffering and lived dispersed around the world. Today this people wants to force the Palestinian people to drink from the same glass," Yasin said in response.
"History will not pardon you and God will judge us all," he said.
He was released and deported to Jordan in 1997 in a deal brokered by the late Jordanian monarch, King Husayn, following a botched assassination attempt by the Israeli secret service Mossad against Khalid Mishal, a Hamas leader in Amman.
Shortly afterwards, Israel allowed the ailing cleric to return to Gaza.
Since then, Shaikh Yasin had an up-and-down relationship with Arafat's Palestinian Authority which has placed him under house arrest several times.