Shortly after returning to Spain, Sardà began his academic career as an assistant professor of at the Faculty of Law and Social and Economic Sciences of University of Barcelona until the end of the civil war.

It was also during that time that he began his career as a public servant when he was named advisor to the Comissaria de Banca, Borsa i Estalvi (Banking, Savings and Stock Exchange Commissioner) in Barcelona.

When he returned to Spain he was a key contributor to the National Stabilization Plan of Alberto Ullastres Calvo y de Mariano Navarro Rubio that brought about the Spanish Miracle.

The main components of the plan called for balancing the national budget, the liberalization of the labor market and international trade and a monetary policy aimed at controlling inflation.

As Sardà's reputation grew, he helped found the faculty of Economics at the University of Barcelona and he was appointed director of the delegations of the International Monetary Fund and the World Bank in Spain.