Later he served as national Vice-Minister of Interior (Political Affairs), in Argentina, in 1963.But he focused mainly on making a living by working as a lawyer and teaching.Indeed, in 1978, O'Donnell launched a major research project on democratic transitions in Southern Europe and Latin America that he co-directed with Philippe C.
At UNSAM O'Donnell founded the Centro de Investigaciones sobre el Estado y la Democracia en América Latina (CIEDAL), in 2010.
and his remains were buried in the Recoleta Cemetery.
He worked as a researcher at IUPERJ (Instituto Universitário de Pesquisas do Río de Janeiro) (1980–82) and then moved to the research center CEBRAP (Centro Brasileiro de Análise e Planejamento) in São Paulo in 1982, replacing the sociologist Fernando Henrique Cardoso, who had become a national Senator.
But O'Donnell moved again, now from Brazil to the United States, in 1983.
He also was a Fellow at the Center for Advanced Study in the Behavioral Sciences, in Stanford, California, in 2002.
O'Donnell also bridged the worlds of academia and politics.
He served as president of the International Political Science Association (IPSA) from 1988 to 1991, and was vice-president of the American Political Science Association (APSA) in 1999–2000.
He also held many short term appointment at universities around the world.
Thereafter, though he maintained his affiliation with CEBRAP until 1991, he taught at the University of Notre Dame from 1983 until 2009, where he was Helen Kellogg Professor of Government and International Studies.
He was also academic director of the Helen Kellogg Institute for International Studies of the University of Notre Dame from 1983 until 1997.