Born in Madrid, she studied at the Royal Conservatory of Music, earning the title of Professor of Voice with the "Premio de Honor" at the end of her studies, as well as a degree in Piano. She holds a postgraduate Master’s Degree in Performing Arts from the Rey Juan Carlos University and a degree in Pharmacy from the Complutense University of Madrid.

Her vocal mentors have included Ana Fernaud and Francisco Lázaro. A scholarship recipient at the Reina Sofía School of Music, she studied in the Alfredo Kraus Voice Chair (1994/95), and later returned to the institution as a voice teacher (2015–2017). She is currently a professor at the Katarina Gurska Higher Center for Musical Education in Madrid, combining her teaching with a career as a soloist and as a permanent member of the Resident Chorus at the Teatro de la Zarzuela in Madrid.

She has received numerous awards, including Best Light Soprano, Best Spanish Performer, and the “Grup de Liceistes 4art i 5è Pis del Gran Teatre del Liceu” Prize at the 1994 Francisco Viñas International Competition. She won First Prize at both the Francisco Alonso and Eugenio Marco Competitions in 1994, and the prize for Best Interpreter of Spanish Opera at the Julián Gayarre Competition that same year. She was also a finalist at the 1996 Queen Elisabeth Competition in Belgium. Her success during the 1996–97 season at the Gran Teatre del Liceu earned her a nomination as “Breakthrough Singer” by the opera press.

From 1998 to 2000, she was a member of the ensemble at the Linz Opera Theatre, and from 2000 to 2006 at the Vienna State Opera. Since then, she has been regularly invited to perform at Europe’s most prestigious venues, including the Deutsche Oper Berlin, Gran Teatre del Liceu in Barcelona, Zürich Opera, Teatro Real and Teatro de la Zarzuela in Madrid, Frankfurt Opera, La Monnaie in Brussels, Teatro de la Maestranza in Seville, Concertgebouw in Amsterdam, Auditorio Nacional in Madrid, Opera Ireland, and the Palacio Euskalduna in Bilbao, among others. Internationally, she has also sung at the Brooklyn Academy of Music, the Musashino Civic Cultural Hall in Tokyo, and the Israeli Opera in Tel Aviv.

Milagros Poblador’s mastery of high-lying coloratura roles such as the Queen of the Night in The Magic Flute, Olympia in The Tales of Hoffmann, Zerbinetta in Ariadne auf Naxos, and Blonde in The Abduction from the Seraglio opened the doors of Europe’s leading opera houses. A specialist in this repertoire, she has performed the role of the Queen of the Night over 190 times internationally, including 54 performances at the Vienna State Opera, making it one of her signature roles.

In the light lyric repertoire, she has portrayed leading roles such as Konstanze in The Abduction from the Seraglio, Gilda in Rigoletto, Amina in La Sonnambula, Norina in Don Pasquale, Adina in L’elisir d’amore, Oscar in Un ballo in maschera, Sophie in both Werther and Der Rosenkavalier, Musetta in La Bohème, as well as roles in Marina and Doña Francisquita. In modern repertoire, her notable appearances include The Soul in Schönberg’s Jacob’s Ladder, Ida in Henze’s The Young Lord, Anne Trulove in Stravinsky’s The Rake’s Progress, The Young Woman in Cerha’s Der Riese vom Steinfeld, The Fire and The Nightingale in Ravel’s L’enfant et les sortilèges, Arde el alba by M. Sotelo, The Mad Scientist in a·Babel by Carlos Galán, and Orff’s Carmina Burana.

She has worked under the baton of renowned conductors such as Lorin Maazel, Leopold Hager, Gabriele Ferro, G. Carella, Gennady Rozhdestvensky, Friedrich Haider, Josep Pons, Odón Alonso, Pinchas Steinberg, Ralf Weikert, Ros-Marbà, Bruno Bartoletti, Anton Guadagno, Seiji Ozawa, Fabio Luisi, Miguel Ángel Gómez-Martínez, and Lionel Bringuier, and with stage directors including Mario Gas, Micha Marelli, Peter Busse, Emilio Sagi, Lindsay Kemp, and others.

Her video recordings include The Magic Flute with the Vienna Philharmonic conducted by Roger Norrington; The Tales of Hoffmann with the Bilbao Symphony Orchestra under Alain Guingal; Un ballo in maschera with the Orchestra of the Teatro Principal in Palma de Mallorca conducted by Renato Palumbo; and Marina, La Traviata, and Rigoletto with the Orchestra of the Teatro Calderón in Madrid conducted by J.A. Irastorza and Tulio Gagliardo, as well as Los Gavilanes with the RTVE Orchestra under Enrique García Asensio.