Gallardo joined the Spanish national archery team in 1995 having won three consecutive national junior titles; at sixteen years old she was the team's youngest member. She made her Olympic debut in 2000 but was eliminated in the first round of the women's individual competition by Anna Karaseva of Belarus.
Gallardo entered the 2004 Summer Olympics as Spain's sole representative in the women's individual event. She began the event with a score of 631 points from a maximum of 720 in the 72-arrow ranking round, earning her the 24th seed for the subsequent elimination rounds. Victories over Georgia's Khatuna Narimanidze and Jasmin Figueroa of the Philippines saw her advance to the last sixteen, where after a poor start she was defeated by Greece's Evangelia Psarra by eight points over eighteen arrows. Although Spanish newspaper El Pais was critical of her performance, stating that she failed to live up to expectations, Gallardo afterwards expressed satisfaction with her result. In the event's final classification, she was placed thirteenth of the sixty-four competing archers.
- "Almudena GALLARDO". Athens 2004. Athens 2004 Organizing Committee for the Olympic Games. Archived from the original on 21 November 2004. Retrieved 17 April 2020.
- Roldan, Ana (24 June 1995). ""En el equipo nacional la edad no cuenta"" [In the national team, age does not matter]. El Pais (in Spanish). Retrieved 16 January 2020.
- "Almudena Gallarado, vigésimo cuarta en arco" [Almudena Gallardo, twenty-fourth in archery]. El Mundo (in Spanish). EFE. 12 August 2004. Retrieved 16 January 2020.
- "Almudena Gallardo y Felipe López abren la participación española" [Almudena Gallardo and Felipe López open Spanish participation]. Diario AS (in Spanish). 11 August 2004. Retrieved 15 January 2020.
- "Almudena Gallardo, vigésimo cuarta en la ronda preliminar de tiro con arco" [Almudena Gallardo, twenty-fourth in the preliminary round of archery]. El Pais (in Spanish). 12 August 2004. Retrieved 15 January 2020.
- "Women's individual archery results". BBC Sport. British Broadcasting Corporation. 13 August 2004. Retrieved 26 January 2009.
- Fernández, Juan José; Roman, Noelia (19 August 2004). "La decepción española, intacta" [The Spanish disappointment, intact]. El Pais (in Spanish). Retrieved 15 January 2020.
- "Almudena Gallardo, primer oro en tiro con arco" [Almudena Gallardo, first gold in archery]. ABC Deportes (in Spanish). 30 June 2005. Retrieved 15 January 2020.