The two worked together to build a business empire.
When Nogueira died in 1893, Braun took over his leases to land in Tierra del Fuego and took control of his commercial, industrial and shipping interests.
She also established an import trading house and group of warehouses, becoming one of the first women to run a business in the area.
Along with her brother, Mauricio Braun, she established the Sociedad Explotadora de Tierra del Fuego (Society for the Exploitation of Tierra del Fuego) in August 1893 to engage in sheep farming.
Through family ties and astute trading, they created a monopolistic company which controlled sheep production in the region and significantly influenced the development of southern Chile.
Involved in many charitable endeavors, Braun was celebrated for her benevolence.
Her mansion is preserved as a museum in Punta Arenas, and the Sara Braun Foundation, established at her death, provides scholarship funds to students for higher education.