Due to practical reasons, filmmakers weren't able to shoot in East Timor. The solution they found was to bring around 24 East Timoreses along with their clothing and fabrics to film in Thailand; completing with extras from Timor who were already in the country, thus bringing the total close to 50. Senhorinha was one of those people, and her scenes were based on a real life encounter Sergio had with a woman from Central Asia in a refugees camp. The actress had also lost her loved ones in the civil war. Even though they were following a script, their dialogue was not rehearsed so the scene was largely improvised and Wagner Moura actually cried during filming.
First narrative feature film of director Greg Barker. 11 years prior to its release, Barker also directed an homonymous documentary depicting Sergio Vieira de Mello's life and the real events pictured in this film. This time, he felt the subject needed a different, more personal approach, focusing on this "big, epic, emotional love story, set against a canvas of political turmoil and change". The new take was inspired by The English Patient (1996), The Killing Fields (1984) and The Year of Living Dangerously (1982).
The actors portraying Adrien and Laurent Vieira de Mello, Sergio's kids, at 5 and 8 years old, are actually Wagner Moura's own children, José Moura and Salvador Moura.
Sergio refused a couple of times UN Secretary-General Kofi Annan's request to accept the Iraq mission as he had just reached a new position at the UN months earlier, but was pressured into it as Annan was being pushed by then US President George W. Bush. After Sergio's death, the US called for Annan's resignation. He then turned to the French, being supported by President Jacques Chirac, and seemingly dodged the responsibility for sending Sergio to Iraq, slipping "the Americans had reached him".
Sergio Vieira de Mello and actor Wagner Moura are both Brazilian. Sergio was from Rio de Janeiro whilst Wagner is from Salvador. Carolina Larriera is Argentinian, whilst Ana de Armas who portrays her is Cuban.