Minister of Foreign Affairs, 2019–2023
Following their best ever result in the 2019 national elections and after becoming part of the incoming governing coalition under the leadership of Prime Minister Antti Rinne, the Green League named Haavisto as the next foreign minister. In this capacity, he chaired the meetings of the Foreign Affairs Council during Finland's rotating presidency of the Council of the European Union in 2019.
In 2019, Haavisto called for the EU to intensify efforts on improving relations with Russia in the face of international conflict, transatlantic tensions and Brexit.
In December 2020, the Parliament's Constitutional Law Committee found that Haavisto, who had pushed for Finnish children from the al-Hawl refugee camp in northern Syria to be brought to Finland quickly in late 2019, had broken Finnish law by trying to replace a foreign ministry official who refused to act after a difference of opinion over the exact repatriation proceedings. The events were leaked to the press causing a political crisis. Haavisto quickly reverted his decision to demote the official and offered him the same position as earlier. The Committee declared it had not found reason to bring criminal charges against the foreign minister, due to the minister's higher than usual prosecution threshold required by the constitution, but specified that Haavisto had operated in contravention to the Administration Law and the Foreign Relations Act. Two Green League MPs published a dissenting opinion and advocated for a softer verdict, causing controversy in the Committee. In Parliament, Haavisto received the Parliament's support in a 101-68 interpellation vote. Haavisto's decision to return the refugees received the Parliament's support on a 110-79 interpellation vote.
In February and March 2021, Haavisto was under criminal investigation for an alleged Highway Code violation in December 2020. The complaint originated from a video recorded by a reporter for the gossip magazine Seiska, which included commentary that Haavisto had not stopped for two pedestrian crossings. The prosecutor who reviewed the video evidence decided not to press charges, citing construction work that had disabled the first crossing and created an unclear situation for the other.
Haavisto was appointed EU's special envoy to Ethiopia during the Tigray War. In February 2021, Haavisto stated that violence and suffering in Ethiopia was "out of control" and could cause a large refugee crisis. In June 2021, he briefed the European Parliament on the conflict. Haavisto warned of a possible ethnic cleansing of Tigrayans, stating that Ethiopia's leaders in closed-door talks said "they are going to wipe out the Tigrayans for 100 years." Ethiopia's foreign ministry dismissed Haavisto's comments as "ludicrous" and a "hallucination of sorts or a lapse in memory of some kind." Haavisto stated that Ethiopian criticism will have no effect on his work as envoy and referred to an upcoming UN human rights report on the situation.
On 17 May 2022, Haavisto signed Finland's application to join NATO. Haavisto visited Kyiv in November, stating that "Finland strongly condemns Russia's illegal invasion of Ukraine. We will continue our firm support to Ukraine as long as necessary."