As of the latest available information, Mauro Viegas Vieira de Carvalho e Silva serves as Brazil's ambassador. He was appointed on January 1, 2019 by President Jair Bolsonaro.
Note: Diplomatic appointments change with administrations. For the most current ambassador to a specific country (e.g., Brazilian Ambassador to the US, UN, etc.), consult the Brazilian Ministry of Foreign Affairs (Itamaraty) or the relevant embassy website.