After six years governing without an absolute majority and with a poor economy, the Socialist Party did worse than expected because of losses in Lisbon and Porto, where polls indicated they had a solid lead.

[7] During his university years, he joined the Group of Light, a club for young Catholics, where he met Father Vítor Melícias, a prominent Franciscan priest and church administrator who remains a close friend and confidant.

He consulted with Portugal's civil society in formulating policy, meeting a range of intellectuals, scientists and entrepreneurs from across the country and the political spectrum in the run-up to the next general election.

[14] He was then one of seven Social Democratic prime ministers in the European Union, joining political allies in Spain, Denmark, Finland, Sweden, Greece and the Netherlands.

Portugal was enjoying an economic expansion that allowed the Socialists to reduce budget deficits while increasing welfare spending and creating new conditional cash transfer programs.

[21] On foreign policy, Guterres campaigned for United Nations intervention in East Timor in 1999, after it was virtually destroyed by Indonesian-backed militias when it voted for independence.

Nevertheless, some long-lasting measures were taken during his second term: in October 2000, the Parliament approved the decriminalization of drug use (effective 1 July 2001)[23] and in March 2001, same-sex civil unions were legalized.

[22][24] In December 2001, following a disastrous defeat for the Socialist Party in local elections, Guterres resigned[18] to "prevent the country from falling into a political swamp".

[27][26] As High Commissioner, Guterres headed one of the world's largest humanitarian organizations, which at the end of his term had more than 10,000 staff working in 126 countries providing protection and assistance to over 60 million refugees, returnees, internally displaced people and stateless persons.

[35] In what was widely considered a very effective PR move, Guterres appointed American actress Angelina Jolie as his special envoy to represent UNHCR and himself at the diplomatic level in 2012.

[36] Together they visited the Kilis Oncupinar Accommodation Facility in Turkey (2012);[37] the Zaatari refugee camp in Jordan (2013);[38] and the Maritime Squadron of the Armed Forces of Malta (2015).

[39] In early 2015, the General Assembly voted to extend Guterres's mandate by 61⁄2 months to 31 December, on recommendation of United Nations Secretary-General Ban Ki-moon.

[40] Guterres left office on 31 December 2015, having served the second-longest term as High Commissioner in the organization's history, after Prince Sadruddin Aga Khan.

[51] During his UNSG informal dialogue, Jamaica, on behalf of the Caribbean Community, asked if the UN should assume liability for any deaths within local populations that result from the introduction of infectious disease by its peacekeepers.

[52] Guterres responded by calling the situation a "particularly complex question", saying it was difficult to preserve diplomatic immunity while also ensuring there is no impunity, but that he would "pay a lot of attention in trying to find the right equilibrium between these two aspects that are absolutely crucial".

[52] In a UN General Assembly meeting in late October 2016, the representative from Haiti called the UN's current and future response to the cholera epidemic "a litmus test of the system's commitment to the promotion of human rights".

[54] In 2016, Anders Kompass exposed the sexual assault of children by peacekeepers in the Central African Republic and, as a consequence, was dismissed by Ban's administration before being rehabilitated in court.

[55] During the United Nations Secretary-General Candidate informal dialogues, Guterres indicated it was completely unacceptable that there be UN forces committing human rights violations such as rape and sexual violence.

Guterres responded by saying an independent jurisdiction would be excellent but that "the only way to get there is through a new compact with all key parties—true contributors, financial contributors—and to make sure that there is an adjustment in the relation between countries, the UN, and the support those that are contributing with troops receive, in order to be able to do it much better.

[59] On 20 June 2017, "Secretary-General António Guterres warned the Trump administration, that if the United States disengages from many issues confronting the international community it will be replaced".

[60] In response to the death of Chinese Nobel Peace Prize laureate Liu Xiaobo, who died of organ failure while in government custody, Guterres said he was deeply saddened.

He urged both sides to "seize this momentous opportunity" and offered UN assistance to achieve the goal of dismantling North Korea's nuclear weapons program.

[68] In August 2018, Guterres called for an independent investigation into a Saudi Arabian-led coalition air strike in Yemen that killed 51 civilians, including 40 children.

[70] In September 2018, during his address to the 73rd United Nations General Assembly, Guterres became the first secretary to say that advancing technology will disrupt labor markets like never before and to advocate stronger safety nets like Universal Basic Income.

"[72] In June 2019, Guterres stated that the "U.N. has the obligation to assume global leadership" in tackling climate change in the context of a visit to the pacific island of Tuvalu.

[73] He had previously supported other multilateral environmental initiatives, such as ecocide becoming a crime at the International Criminal Court and the Global Pact for the Environment that was put forward by France in September 2017.

[82] On 10 August 2020, responding to an explosion in Beirut, Guterres expressed his support for all people in need in Lebanon, especially women and girls who are most vulnerable in times of crisis.

[85] On 6 October 2020, Guterres expressed deep concern over the escalation of hostilities in the disputed region of Nagorno-Karabakh and called on Armenia and Azerbaijan to immediately halt fighting and progress towards a peaceful resolution.

[93] On 22 July 2022, together with Turkey, the United Nations under the leadership of Guterres brokered a deal between Russia and Ukraine clearing the way for the export of grain from Ukrainian ports.

[99] Guterres condemned the actions of Hamas during the 2023 Israel–Hamas war, but said he was "deeply distressed" by Israel's decision to impose a total blockade on the Gaza Strip.