Riad Abdel Karim al-Raz, 47, also the head of the engineering department at Al-Najah University in Nablus was freed on Friday with torn clothing and a black eye. He said he had no idea who kidnapped him or what they wanted.
"People came and took me by force. They didn't treat me well, and then they apologised and told he I would be taken home," he said.
Asked whether he thought the kidnappers were affiliated with the ruling Fatah movement, which is competing with Hamas in upcoming parliamentary elections, al-Raz said: "I'm not sure myself who they are."
The Al-Aqsa Martyrs Brigades, a resistance group linked with Fatah, denied involvement.
Al-Raz was seized from his home in the town of Tulkarim late on Thursday by Arabic-speaking masked men, his wife said.
She said the men, firing in the air, pounded on the door of their home and then escaped with her husband.
Al-Raz is a political leader of Hamas in the area.