Palestinian Authority President Mahmoud Abbas asserted, "Today, and after announcing the government of national unity, we declare the end of division that caused catastrophic harm to our cause."
The swearing-in ceremony was held Monday in Ramallah.
Plans to establish a unity government were announced on April 23, following a stalemate of U.S.-led peace negotiations between Israel and the Palestinian Authority.
The unity agreement reunites both Gaza, formerly overseen by the Palestinian Liberation Organization, and the West Bank, previously controlled by Hamas, under a shared political authority for the first time since 2007.
The decision to form a unity government was met by harsh criticism from Israel, with Israeli Prime Minister Benjamin Netanyahu cautioning that "Abu Mazen [Palestinian Authority President Mahmoud Abbas] needs to choose between peace with Israel and an accord with Hamas."
U.S. Secretary of State John Kerry, his spokesperson said, is taking a wait and see approach: "As we've said all along, we'll not make decisions until we see the final formation of the interim government and have the opportunity to assess and make a determination about whether this is a government we can work with. And we will base that assessment on the government's composition, policies, and actions."