Completing 28 months of solitary confinement on Thursday, Hasan Yusuf walked out of Israel's Ofar prison just west of Ram Allah and immediately headed towards Yasir Arafat's grave to pay his respects.
Later, Yusuf told Aljazeera despite his two-year ordeal, he was still in Hamas and would remain in the organisation until Palestinian's obtained their rights.
"I have faced what every Palestinian detainee faces in the Israeli jails: investigations, solitary confinement and torture," Hasan Yusuf said.
"I appeal to the Palestinian people, Authority, all factions and forces, saying that the detainees are their responsibility," he added.
The 49-year-old said there could never be a real peace with Israel until all Palestinian detainees held in Israeli jails had been released.
Yusuf was jailed for his ties to Islamic charities affiliated with Hamas, which has spearheaded a campaign of resistance in the face of Israeli occupation in Gaza and the West Bank.
His release from prison might bolster Hamas's ranks in the West Bank amidst a power vacuum following Arafat's death.
According to Israel's Haaretz newspaper's website, the Jewish state's Shin Beth security service was unable to provide evidence connecting Yusuf to attacks by Hamas. He was convicted on the relatively minor charges of links to illegal charities.
He served most of his sentence at a prison in the al-Saba military prision.