She was later appointed as the Regional Director for South America at the International Union for the Conservation of Nature (IUCN), a position she held from 2005 to 2007 before transitioning into her political and diplomatic career.

Her early work involved collaboration with civil society organizations and academic institutions, eventually leading her to serve as an advisor on biodiversity and climate change policy.

Espinosa founded and directed the Socio-Environmental Studies Program at the Latin American Faculty of Social Sciences (FLACSO) in Quito from 1996 to 1999, further solidifying her role as a leader in environmental issues.

She positioned IUCN as a crucial regional stakeholder, recognized as an authoritative expert, technical assistance provider, and advocacy leader on environmental issues.

Under President Rafael Correa, María Fernanda Espinosa held multiple key roles in the Ecuadorian government, reflecting her versatility and expertise across various domains.

Her contributions extended to environmental and climate change negotiations, and she actively engaged in discussions on South-South cooperation and system-wide coherence, including the establishment of UN Women.

Her leadership in the Yasuní ITT Initiative, which sought to avoid CO2 emissions by leaving oil reserves untapped in exchange for international compensation, marked a significant contribution to global environmental discourse.

Espinosa led reforms in social security management, education, training, and health policies for military forces, and she was instrumental in creating the National Defense Political Agenda 2014-2017.

Her tenure also saw the establishment of a Gender Equality Policy within the Armed Forces and the convening of the first international cooperation network of Women Ministers and Leaders of Defense.

Espinosa’s efforts modernized the Armed Forces, adapting them to the new constitutional framework and addressing contemporary security threats such as cybersecurity, organized crime, and natural disasters.

In October 2014, María Fernanda Espinosa was appointed Permanent Representative of Ecuador to the United Nations and other international organizations in Geneva, Switzerland, a position she held until May 2017.

Her work was a milestone in the Council's deliberations, as it was the first time the implications of transnational corporations on human rights were discussed for consideration in a legally binding instrument.

In her capacity as Permanent Representative, she defended the Ecuadorian Government's decision to grant political asylum to Julian Assange in a discussion on arbitrary detention in September 2016 as a matter of international law and human rights.

She held several high-level events on women’s empowerment and political participation and gathered woman Heads of State and Government and other leading female figures to advance the gender equality agenda.

[26] Before starting her political and diplomatic career, Espinosa was Associate Professor and Researcher at the Latin American Faculty of Social Sciences FLACSO, where she established and coordinated the Program on Socio-Environmental Studies.

She served as advisor in biodiversity, climate change, and indigenous peoples’ policies (1999-2005), and later as regional director for South America of the International Union for the Conservation of Nature UICN (2005-2007).

[45][circular reference] - The Orden “El Sol del Perú” (The Order of the Sun of Peru), Gran Cruz (Grand Cross) class, February 23, 2007.