[1][2] The diversified business empire he created played a key role in helping to link Argentina with the trading and financial systems of the first world.

On his return to Argentina he took up a job working for a company directed by his brother-in-law which exported wool and leather and imported agricultural machinery.

The company also invested in railways and acquired land in the provinces of Santa Fe and Entre Rios, previously occupied by Indians.

[2] Amongst other activities the Tornquist group organised the hunting of whales (not controversial in those days) around the South Georgia Islands through the Compañía Argentina de Pesca, oil exploration in Mendoza, the exploitation of quebracho in Santiago del Estero and the construction of the Ferrocarril del Norte de Santa Fe with the help of Belgium capital.

Ernesto Tornquist played a crucial role in helping to avoid a war between Argentina and Chile in 1902 by managing the British mediation in the border dispute, and by strongly opposing the bellicose Foreign Minister Estanislao Zeballos.