Born in Resistencia, Chaco in a traditional family, Carrió was a former teenage beauty queen. After the return of democracy, she was elected to the Chamber of Deputies for her province, representing the Radical Civic Union (UCR).

Asked by her mentor, Raúl Alfonsín, she campaigned heavily for Fernando de la Rúa in 1999.

After the breaking of the coalition with the Socialists and the Front for a Country in Solidarity (FrePaSo) in 2000, Carrió turned to the Democratic Socialist Party and other politicians with left leanings who were discontented in their parties, and formed an informal front, initially called "Argentinians for a Republic of Equals" (Argentinos por una República de Iguales), ARI. After dissensions, the socialists left, and so did Carrió and other personalities from their original parties. Together, they formed a new party, called Alternative for a Republic of Equals (also ARI).

In the 2003 elections, Carrió was candidate for her party, obtaining fifth place with about 14% of the votes (the votes were scattered; the first-turn winner, Carlos Menem, only got 24%, but stepped down before the runoff). In 2005, Carrió was reelected as a deputy for the Autonomous City of Buenos Aires.

Carrió ran again for the presidency on the 2007 elections, representing a front called the Civic Coalition. In March 2007 she resigned her seat in Congress to conduct the campaign. Together with her running mate Rubén Giustiniani (chairman of the Socialist Party), Carrió obtained about 23% of the vote, coming in distant second after Cristina Fernández de Kirchner. She won the majority vote in two of the three largest cities of Argentina (Buenos Aires and Rosario), but she suffered a larger defeat in Buenos Aires Province, the most populated district, and could not force a runoff election.

After the election, Carrió announced she would not be running for the presidency again, but will instead acknowledge her role as "leader of the opposition" and help others in her movement to reach the government in 2011.