The shadowy Hamas military chief killed in an Israeli missile strike Wednesday had long topped the Jewish state's most-wanted list for masterminding a string of deadly attacks.
One was the 2006 capture of an Israeli soldier in a complex cross-border raid that killed two other soldiers.
Ahmed Jabari, a former history student who spent 13 years in Israeli prisons, also commanded Hamas fighters during a 2007 takeover of Gaza in which they drove out forces loyal to Palestinian President Mahmoud Abbas.
During nine years as leader of the Hamas Izzedine al Qassam Brigades, Jabari largely stayed out of the public eye. His highest profile appearance came in October 2011, when he escorted the captured Israeli soldier, Sgt. Gilad Schalit, out of Gaza in a swap for about 1,000 Palestinian prisoners held by Israel.
In a public appearance late Wednesday, Israeli Defense Minister Ehud Barak called Jabari "the military chief of staff of Hamas."
Jabari was born in 1960 in Gaza City. He began as a member of Abbas' Fatah movement, but switched his allegiance to Hamas during his time in Israeli prisons.
After Israel released him in 1995, he worked for a Hamas-run support group for prisoners. In 1998, he was jailed by Palestinian security forces in Gaza for his involvement with the Hamas military wing. Jabari was released two years later, after Israel shelled Gaza prisons as part of its crackdown on a Palestinian uprising.
In 2003, Jabari became the de facto commander of the Hamas military wing after then-chief Mohammed Deif was seriously wounded in an Israeli attack. Jabari survived four attempts by Israel to kill him. In 2004, an air strike on Jabari's house killed his son, Mohammed, a brother and three other relatives.
Israel withdrew from Gaza in 2005 but still controls its airspace, seacoast and all but one of its land crossings.
Hamas has ruled Gaza with an iron hand since the 2007 takeover, deepening the political split with Abbas. Repeated attempts at reconciliation have failed.
The takeover deepened the isolation of Hamas and prompted the group to rely increasingly on Iran and Syria. Jabari was instrumental in developing the Hamas military arsenal and the group's networks in Iran, Sudan and Lebanon.
The Hamas founding charter calls for the destruction of Israel, though the group has been grappling with its political direction in recent years.
Founded in Gaza in 1987, Hamas carried out scores of suicide bombings in Israel, killing hundreds of Israelis, but halted most such attacks several years ago. Gaza militants, including those from Hamas, have fired thousands of mortars and rockets at Israel in the past decade, drawing Israeli retaliation.
Jabari was considered close to Hamas hard-liner Mahmoud Zahar, a Gaza strongman. In 2011, Jabari wrote in a Hamas publication that "as long as the Jews occupy our land, they have one thing (in store), death, or they leave the occupied Palestinian territories."