Following his release, Taiana held several academic positions until he was appointed Advisor to the Foreign Affairs Committee of the
Argentine Chamber of Deputies (1987–89). He was appointed Undersecretary for Organizations and Special Matters after the election of fellow Peronist
Carlos Menem in 1989, and in 1990 was appointed Undersecretary for Foreign Policy and later Director of International Organizations (1991). Between 1992 and 1995, he was the Argentine Ambassador to
Guatemala and concurrently to
Belize. After wide regional support to his candidature, he served as Executive Secretary of the
Inter-American Commission on Human Rights of the
OAS between 1996 and 2001, and then became Secretary for Human Rights of the Government of the
Province of Buenos Aires. President Kirchner appointed Taiana as Minister of Foreign Affairs, International Trade and Worship in December 2005, replacing
Rafael Bielsa; Taiana had been Bielsa's Deputy since 2003. During his time as foreign minister, a parallel embassy was established in Venezuela under the leadership of Claudio Uberti, who developed businesses with money that later financed the Kirchners' political campaigns. The affair became public knowledge when Antonini Wilson entered the country with suitcases containing $800,000. He resigned his post on 18 June 2010, citing "lack of support and differences" with the President. He remained generally supportive of her administration, however, and in September was nominated to head the
Front for Victory party list for the
Buenos Aires City Legislature.
National Senator In the
2017 legislative election, Fernández de Kirchner announced her candidacy to the
Argentine Senate in
Buenos Aires Province as part of
Unidad Ciudadana, and Taiana was announced as the second candidate in the list. The Fernández de Kirchner–Taiana ticket came second in the general election, with 37.31% of the vote. In the electoral system for the upper house, this meant that only Fernández de Kirchner was elected as the senator for the minority. Following the
2019 general election, however, in which Fernández de Kirchner was elected
vice president alongside
Alberto Fernández, her seat in the Senate was left vacant, and Taiana was sworn into office in her stead on 27 November 2019.
Defense Minister On 9 August 2021,
Cabinet Chief Santiago Cafiero confirmed Taiana would be the next
Minister of Defense of Argentina, in replacement of
Agustín Rossi, who resigned to focus on his campaign to the
Senate in the
2021 legislative election. Taiana was one of two ministerial replacements ahead of the 2021 election, alongside
Juan Zabaleta, who replaced
Daniel Arroyo as Minister of Social Development. His vacancy in the Senate was filled by
Juliana Di Tullio.
Chamber of Deputies In August 2025, Taiana was confirmed as a Unión por la Patria in Buenos Aires Province candidate for the Chamber of Deputies. He led the list that came together from an agreement among ex president Cristina Fernández de Kirchner, and current Buenos Aires province governor Axel Kicillof. ==Honours and awards==