Palestinian lawmakers endorsed the cabinet, later sworn in by President Mahmoud Abbas of Fatah, after Haniyeh announced a platform declaring that "resistance in all its forms, including popular resistance to occupation, is a legitimate right".
The US called on the new Palestinian government to renounce violence, recognize Israel and respect peace agreements.
"The national unity government's platform reference to the right of resistance is disturbing and contradicts the Quartet principles of renunciation of violence," Nancy Beck, a US state department spokeswoman, said.
"The prime minister's speech to the Palestinian Legislative Council was disappointing and inconsistent with the Quartet principles as well as the National Unity Government's adherence to the foundational principles of peace."
Shortly after the confidence vote was passed , Norway announced its recognition of the new Palestinian government.
"We recognise it [the Palestinian government] as it has recognised the international agreements," Jonas Gahr Stoere, the Norwegian foreign minister, told Al Jazeera.
"We see that [its commitments] clearly, and on this basis we think that it is important to send a signal that we are now prepared to deal actively with the government. We hold it responsible to follow words with deeds……this is an additional aspect of the political process in the region", he said.
Al Jazeera's correspondent in Oslo reported that Norway was ending economic sanctions against Palestinians.
The European Union also welcomed the establishment of a Palestinian unity government but said a resumption of aid would depend on an assessment of the new cabinet's actions.
"The Presidency of the EU recalls the readiness of the EU to work with and to resume its assistance to a legitimate Palestinian government adopting a platform reflecting the Quartet principles. The EU will carefully assess the platform and actions of the new government and its ministers," an EU statement said.
Hamas to seek end to 'occupation'
Before the confidence vote, Haniya spelt out the new administration's policies.
"The government will work with the international community to put an end to the occupation and recover the legitimate rights of our people," he said.
The government would attempt to build a Palestinian state on the lands occupied by Israel in 1967, Haniya said.
The coalition government would also attempt to reach a prisoner exchange deal with Israel, the senior Hamas leader said.
In his speech before the vote, Abbas called for a negotiated peace with Israel and a rejected "all forms of violence".
The Palestinian president also urged Western powers to lift their international boycott of the Palestinian Authority.
Western powers have demanded that the Palestinian government recognise Israel, renounce violence and abide by previous peace agreements.
But it remains to be seen what effect, if any, the coalition government between rival Hamas and Fatah has on international relations.
The new government is likely to pledge "respect" for past Palestinian-Israeli agreements, in line with a Saudi-brokered agreement reached by Hamas and Fatah in Mecca on February 8.
Following Haniya's speech, Israel re-iterated its position that it would not deal with the incoming government.
"This is just a ploy to regain international hand-outs with smoke and mirrors"
LeotheIsaurian, Detroit, US
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Miri Eisin, a government spokeswoman, said: "Israel will not recognise or work with this new government or with its members."
"And not only is there no renunciation of terrorism, there is a clear call by the new prime minister to what he calls the right of resistance.
"We expect the international community to firmly stick to its demands concerning the three conditions."
Ziyad Abu Amr, Palestinian foreign minister in the new administration, told Al Jazeera that the unity government was willing to talk to Israel.
"This is a unity government not a Hamas government. We are ready to deal with the Israelis if they are ready."