Ismail Haniya was a relatively unknown figure until he headed the Hamas list that won the Palestinian legislative election of January 2006.
Ismail Haniya is one of Hamas' leaders in Gaza
He had risen within the Islamic group as a close associate of its spiritual leader, the late Sheikh Ahmad Yassin, whose office he ran.
He is considered a pragmatist in the movement's ranks who is more open to dialogue with Israel.
However, he has insisted that Israel would have to recognise Palestinian rights before talks could begin.
Mr Haniya was born in 1962 in the Shati refugee camp to the west of Gaza city, after his parents fled their home near what is now the Israeli town of Ashkelon during the 1948 Arab-Israeli war.
Haniya was detained three times during the first intifada
He studied Arabic Literature at the Islamic University of Gaza, where he became involved in the Islamist movement.
Mr Haniya graduated in 1987, just as a mass uprising, or intifada, against the Israeli occupation erupted in Gaza.
He was detained by the Israeli authorities for participating in protests soon afterwards, though his prison sentence was short.
In 1988, with Hamas coming to the fore in Gaza as a leading resistance movement, he was again detained, but this time imprisoned for six months.
The next year, with Israel unable to quash Palestinian resistance, Mr Haniya was arrested yet again and sentenced to three years in prison.
Following his release in 1992, Israel deported Mr Haniya along with senior Hamas leaders Abdel-Aziz Rantissi and Mahmoud Zahhar and over 400 other activists to South Lebanon.
The activists spent more than a year camped at Marj al-Zahour, where the Islamist group received unprecedented media exposure and became known throughout the world.
Mr Haniya returned to Gaza in December 1993 and was appointed dean of the Islamic University.
After Israel released Sheikh Yassin from prison in 1997, Mr Haniya was appointed his assistant.
The two men's close relationship led to Mr Haniya gaining increasing prominence within the movement and he became the group's representative to the Palestinian Authority.
With his high profile, however, came the threat of Israel's policy of eliminating Hamas' military and political leaders.
Sheikh Ahmad Yassin and Haniya were targeted by Israel
In September 2003, Mr Haniya and Sheikh Yassin were slightly injured in an Israeli air strike on an apartment block in Gaza City.
The two men left the building seconds before the bomb struck, after hearing the approaching Israeli aircraft.
Only six months later, Sheikh Yassin was killed by Israeli helicopter gunships as he left a mosque after dawn prayers.
When Sheikh Yassin's successor in Gaza, Abdel-Aziz Rantissi, was killed by Israel in April 2004, Hamas decided to keep the name of its new leader in Gaza secret.
But Palestinian sources said Mr Haniya was appointed to the group's "collective leadership" with Mahmoud Zahhar and Said al-Siyam.
Although Mr Zahhar is thought to be the most senior of those leaders, Mr Haniya was chosen to lead Hamas' campaign for the 15 January election.
Mr Haniya led the 'Change and Reform List' in the January election
Mr Haniya and his party appealed to mainstream Palestinian voters and they won 76 seats out of 132 in the Palestinian Legislative Council.
Hamas was then asked by the Palestinian leader, Mahmoud Abbas, to form a new government.
However, weeks of negotiations on a coalition with the former ruling Fatah party and other factions failed and Mr Haniya was forced to name a cabinet primarily formed of its own members and several technocrats.
When he outlined his administration's programme, Mr Haniya urged the US and EU not to carry out their threats to cut funding to the Palestinian Authority unless Hamas renounced violence and recognised Israel.
He stressed the Palestinians were entitled to continue their struggle for independence, but at the same time said he wanted to hold talks with international mediators about solving the conflict.
"Our government will spare no effort to reach a just peace in the region, putting an end to the occupation and restoring our rights," he said.