Staffan de Mistura, who has held top U.N. positions in Iraq and Afghanistan, on Thursday inherited the mandate to try to end Syria's three-year-old conflict, a goal that eluded his two predecessors.
Secretary-General Ban Ki-moon said he chose the Swedish-Italian diplomat as the U.N. point man on Syria because of his work at the United Nations for 40 years, including delicate and difficult jobs as the U.N. special representative in Iraq and Afghanistan. De Mistura replaces Lakhdar Brahimi, who resigned May 31 after nearly two years of failed efforts to end the worsening civil war.
Ban said he consulted broadly before making a decision, including with the Syrian government.
Unlike Brahimi, de Mistura will not be joint envoy of the U.N. and the Arab League, which has been deeply divided over the war in Syria.
Ban stressed, however, that close coordination and cooperation with the Arab League is "a basic hallmark of our work until now and it will continue to be so."
The secretary-general also announced the appointment of Egyptian Ambassador Ramzy Ezzeddine Ramzy, who was recommended by the Arab League, as de Mistura's deputy.
Brahimi had followed in the footsteps of his longtime friend, former U.N. Secretary-General Kofi Annan, who resigned from the same job in August 2012 after failing to broker a cease-fire as the country descended into war.
Ban cast some blame for Brahimi's failure on Syria's rebels but was especially critical of President Bashar Assad's government, the divided U.N. Security Council, and feuding influential nations for failing to help him achieve a peace agreement.
With the Syrian government on the offensive, rebel divisions deepening and the takeover of areas near the Iraqi border by the Islamic State extremist group, de Mistura faces an uphill struggle getting the warring parties back to the peace table.
Ban said the job requires "very skillful diplomatic efforts" and de Mistura "will bring all his expertise and experiences to ... very difficult negotiations for peace in Syria."
The new special envoy will be engaging with key players inside and outside Syria "in order to end violence and facilitate a peaceful Syrian-led and inclusive political solution that meets the democratic aspirations of the Syrian people," Ban said.
"I call on the international community, including in particular the Security Council and the Syrian parties, to give Mr. de Mistura unified support in order to allow him to succeed in his mission," the secretary-general said.
Born in Stockholm, De Mistura, 67, recently served as deputy foreign minister in the Italian government headed by Mario Monti. He speaks seven languages, including colloquial Arabic, according to the Italian Foreign Ministry.
British Foreign Secretary William Hague welcomed his appointment "at a time when the need for a political settlement in Syria has never been more pressing."
U.S. Ambassador Samantha Power said de Mistura throughout his career "has proven a tenacious and creative problem solver, and a tireless champion of peace, security and human dignity."
She said the United States stands ready to work with him as he faces the challenge of ending the violence and "catastrophic suffering" of the Syrian people.
Najib Ghadbian, U.N. representative of the opposition Syrian Coalition, his groups looks forward to working with de Mistura to achieve "a political transition to democracy."
Camilla Jelbart Mosse, who heads Syria operations for the aid agency Oxfam, said de Mistura's knowledge of the region "will be key to his mission."
With the Syrian people clamoring for an end to the fighting, Mosse said de Mistura's mandate should include building international support for locally negotiated cease-fires and encouraging an end to sieges of towns and cities and the starvation of civilians.