Ms Mercedes Araújo Díaz de Terán was born in Barcelona to parents from western Spain on 3 July 1969, the fourth of six siblings.
She was educated in the Autonomous Community of Madrid: at the state primary school "Nuestra Señora de la Concepción", at state secondary school in Pozuelo de Alarcón, and at Complutense University, where she graduated in law in 1992.
In September 1995 she became a legal advisor to Parliament and has spent her entire professional career to date at the Congress of Deputies, holding successive assistance and advisory posts in the bureau of the Congress of Deputies, on Boards of Party Spokespersons and in Plenary Sessions of the 6th to the 15th legislative bodies, under Mr Federico Trillo-Figueroa, Ms Luisa Fernanda Rudi, Mr Manuel Marín, Mr José Bono, Mr Jesús Posada, Mr Patxi López, Ms Ana María Pastor, Ms Meritxell Batet and Ms Francina Armengol.
From 6 October 1995 to 7 April 1997, she served as a legal advisor to Parliament at the Directorate for Technical-Parliamentary Assistance; from 8 April 1997 to 7 November 2000, she was Head of the Legal Assistance Department at the same Directorate; from 8 November 2000 until 10 March 2014, she was Director of Technical-Parliamentary Assistance; from 11 March 2014 to 29 January 2024, she was Deputy Secretary-General for Administrative Affairs and from 30 January to 29 November 2024, she served as Deputy Secretary-General for Parliament.
As a legal advisor to Parliament, she has provided services to a number of different committees, including the Budget Committee and the Regulations Committee.
She has been secretary of the Spanish delegation to the NATO Parliamentary Assembly, and Data Protection Delegate of the Congress of Deputies.
She has formed part of the examination tribunals for various civil service bodies at Parliament: Editors, Stenographers and Shorthand Typists (2007), Technical-Administrative (2018 and 2020), Specialist Advisors (2013) and Counsel (2022). She was also a member of the Selection Committees for the competitive recruitment process for non-civil service staff at the Congress of Deputies: Guides (2015), Maintenance Brigade (2019), Nurse/Technical Health Assistant/Nursing University Diploma Graduate (2021), IT auxiliaries (2021), Programmers (2019 and 2022) and Analysts (2021).
She is married and has one child.
She was appointed Secretary-General of the Household of His Majesty the King by virtue of Royal Decree 1215/2024 of 29 November 2024.