In his professional activity he worked as a consultant and economic advisor to companies, international investors and financial institutions in Argentina and Latin America. He was a consultant to the Inter-American Development Bank, World Bank, International Monetary Fund and chief economist of the Latin American Economic Research Foundation.
Enjoying little political support from President, Fernando de la Rúa, he was fired within two weeks after a wave of protest over his proposed fiscal austerity project, by which he sought to prevent the 2001 economic crisis but which sharply cut public spending.[7]
He later teamed with Mauricio Macri in 2005 to create a new center-right coalition called Republican Proposal (PRO), which tacitly supported his unsuccessful second bid to the presidency in the 2007 presidential election. López Murphy did poorly, gaining just 1% of the vote; PRO, however, did somewhat better in provincial and congressional elections, and won the mayoral election in Buenos Aires that year.
I follow the Argentine liberal tradition of [Juan Bautista] Alberdi, [Leandro] Alem and [Marcelo T.] Alvear. I am very proud of that. My ascription to liberal theories is not economic. That is a minor issue. I am part of a philosophical and moral tradition that has to do with defending the division of powers, controlling whoever exercises power, ensuring equality before the law and preventing someone from claiming the project of my happiness. With having the freedom and autonomy to decide my own future. I think it is very bad that the defense of liberal ideas is in charge of economists, because in general they start on the wrong side.