In 2015, Gallardo auditioned for the first season of the Chilean vocal talent show The Voice Chile with the song "The Story" by American singer Brandi Carlile, after her performance she chose Luis Fonsi as her coach, she would eventually end at second place in the competition.

[1] Later, she was signed with Universal Music and released her debut single "Más de la Mitad" in 2016, the song was written by Luis Fonsi and Claudia Brant and was produced by Andrés Saavedra in Miami, United States.

[7] In early January 2018 she released the singles "Ven" and "No es Real", the latter with Spanish singer Antonio José, her debut studio album Rosa was released on June 8, 2018, and was certified platinum in Chile selling over 55,000 copies, the album was promoted by several concerts including one at the Movistar Arena in Santiago, Chile, making Gallardo the youngest Chilean artist to perform at the venue.

[10] At the 20th Annual Latin Grammy Awards, also in 2019, she was nominated for Best New Artist and Best Traditional Pop Vocal Album, she also performed at the Person of the Year ceremony, given to Colombian singer Juanes in that year, where she performed the song "Fotografía" alongside Colombian band Morat and Spanish singer Pablo López.

[16] During 2020 and 2021, she collaborated with artists like Spanish singer Alba Reche in "que bailen", about the protests in Chile, and Colombian band Morat in "Simplemente Pasan".