From 2009 to 2013 she was part of the United Nations' Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW) Committee, and from 2011 to 2015 she was a member of the City Council of Salamanca [es] for the Spanish Socialist Workers' Party (PSOE).

[5][6] She served during the eighth legislature (2004–2008) presided over by José Luis Rodríguez Zapatero, a period in which she promoted the Organic Law on Comprehensive Protection Measures Against Gender Violence [es].

[9] She was a full professor of the Department of Sociology and Communication at the University of Salamanca's Faculty of Social Sciences[10] when in June 2018 she was appointed Secretary of State for Equality at the proposal of the Vice President of the Government and Minister of the Presidency, Relations with the Courts, and Equality, Carmen Calvo, in the government of Pedro Sánchez.

[11] In various publications Murillo denounces the social devaluation of the private and domestic sphere despite the number of hours invested in the production of household goods and services, as well as the care of dependents, which also requires the existence of a person responsible for their organization, usually a woman.

[12] In it she denounces how women's groups perceive the discriminatory treatment to which they are subjected by the public powers, and as a result they consider that it is usual for political parties not to recognize their achievements, however important they have been, or that have helped to create social welfare.