Echegui landed her first television work with a minor role in the series
Una nueva vida, followed by an appearance in the series
Paco y Veva. For her big screen debut, Echegui starred in
Bigas Luna's
My Name Is Juani, portraying the title character, a 18-year-old woman who moves to Madrid to pursue her dreams of becoming an actress. Reviewing for
Variety, Jonathan Holland assessed that Echegui "revels in the role of the raspy-voiced, short-skirted and irrepressibly vulgar Juani, the character who comes closest to winning viewers' hearts". Early roles also include her appearance in the TV movie
Un difunto, seis mujeres y un taller. Likewise, the film
8 Dates, presented at the 2008
Málaga Film Festival, gave her the opportunity to try her hand at comedy. She also trained to acquire an
Argentine accent for her role in the
Basque conflict-themed film
La casa de mi padre (2008), which premiered at the
San Sebastián International Film Festival. '' co-stars
Mark Waschke and
Teun Luijkx Echegui's portrayal of a "gutsy, streetwise" convict seeking redemption in the prison drama
My Prison Yard (2008) won her her first nomination for the
Goya Award for Best Actress. The
European Film Promotion Jury selected Echegui as one of ten up-and-coming European actors to receive the 2009
Shooting Stars Award. In 2009, she co-starred in the British comedy
Bunny and the Bull as a lively Spanish waitress, her first international film appearance. She also played a part in the Madrid-set spy thriller
The Cold Light of Day (2012), which received negative feedback from critics and audiences alike. She portrayed a woman in a love triangle in the ensemble comedy
Family United (2013), set against the backdrop of the
2010 FIFA World Cup final. In 2016, she co-starred as an aspiring novelist opposite to
Gael García Bernal in the Mexican film ''
You're Killing Me Susana, and along with David Verdaguer and Álex García in a love triangle in the romantic comedy Don't Blame the Karma for Being an Idiot'', after prior cast choice
Clara Lago withdrew from the project. Echegui was invited to membership in the
AMPAS in 2018. In 2020, Echegui co-starred in the jukebox musical comedy
My Heart Goes Boom!, featuring songs by
Raffaella Carrà. For her supporting role in the film she landed another Goya nomination, as well as a
Feroz Award for Best Supporting Actress in a Film. Echegui went on to win the Gaudí Award for Best Supporting Actress for her role in
The Offering (2020), a drama halfway between "Greek tragedy and psychological thriller" playing a deeply traumatised woman surrounded by toxic relationships. She also portrayed hard-boiled cop and
cosplay-loving Norma in
Unknown Origins. . In 2021, she debuted as a director with the short film '''', which won her the
Goya Award for Best Fictional Short Film. The short film's story tackled structural gender-based violence. and in the 2023 historical drama miniseries
The Patients of Dr. García as a
Falangist woman from a wealthy family. In 2024, she starred in the coming-of-age comedy
Yo no soy esa, and as a judge in
Artificial Justice, a thriller set in a near future delving on the meddling of
artificial intelligence in the justice system. In 2025, Echegui starred in the romantic comedy series
Love You To Death. Her work in the series
Ciudad de sombras, and in Sara Sálamo's film
Hortelana, will be released posthumously. == Personal life and death ==