A member of the Justicialist Party, Di Tullio served three terms as National Deputy representing Buenos Aires Province, from 2005 to 2017.

During her time in the lower chamber of Congress, Di Tullio was known for sponsoring a number of bills that expanded the rights of women and LGBT people in Argentina.

[10] During her third term in the Chamber of Deputies, Di Tullio presided the FPV bloc, becoming the first woman to lead a parliamentary caucus in the history of the Argentine Congress.

[4][11] She was also part of the Commerce, Human Rights, Women and Childhood, General Legislation and Foreign Affairs parliamentary commissions.

[17] In 2021, Taiana was sworn in as Defense Minister, and Di Tullio was then tapped to take his seat in the senate for the remainder of the 2017–2023 term.