Sergio

The real Carolina Larriera wrote a piece in The Huffington Post criticizing the surprising lack of initiative on the part of the United Nations to look into an attack of such magnitude and bringing those responsible to justice even though Sergio had been an indispensable asset to the organization. She claims the bombing that killed him was never properly investigated and "the circumstances of the incident were buried under statues and memorial speeches." Larriera resigned from the UN in 2005.

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.

Shortly after the events seen in the film, Carolina Larriera spoke out about the mistreatment from the United Nations and how they tried to keep her away from Sergio's funeral, claiming they weren't formally married and depriving her of rights as both family and employee. Larriera wasn't allowed to keep their personal belongings from Baghdad, UN didn't hear her testimony and her name was removed from the list of survivors of the attack. Despite the two having been engaged with total support from Sergio's family, their civil union was only legally acknowledged after a lawsuit that lasted for over 10 years against his first wife Annie Personnaz. Even then, the UN remained silent.

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.