He was chairman of the Argentine Industrial Union, director of the National Bank of Argentina, and Minister of Production during the presidency of Eduardo Duhalde.

Upon attaining his degree, De Mendiguren worked at a private bureau as a specialist on corporate law and as a foreign investment advisor.

De Mendiguren founded an industrial group that presently includes a textile company and a sports-related products chain.

[7] In 2002, in the aftermath of the 2001 economic crisis, interim president Eduardo Duhalde appointed De Mendiguren as Minister of Production.

[11] His second presidency corresponded to a period of political friendship with the government of Cristina Fernández de Kirchner, with whose administration the industrial sector had previously been generally at odds.

[12] Ahead of the 2013 legislative election, De Mendiguren was selected as the fifth candidate to the Argentine Chamber of Deputies in the Renewal Front list in Buenos Aires Province.