Born and raised in a favela in Rio de Janeiro, Soares took part in a singing contest presented by the renowned Brazilian musician Ary Barroso, and received the highest marks. In the late 1950s, Soares spent one year touring Argentina with Mercedes Batista. Soares became popular with her first single "Se Acaso Você Chegasse", on which she introduced the scat à la Louis Armstrong, adding a bit of jazz to samba. She moved to São Paulo, where she performed at theaters and night clubs. Her husky voice became her trademark. After finishing her second album, A Bossa Negra, Elza went to Chile to represent Brazil in the 1962 Football World Cup. Her outgoing and over-the-edge style fascinated audiences in Brazil and abroad.
In the 1970s, she toured the U.S. and Europe. She has been singing for more than 40 years. In 2000, she was awarded "Best Singer of the Millennium" by the BBC in London, where she performed in a concert with Gal Costa, Chico Buarque, Gilberto Gil, Caetano Veloso and Virgínia Rodrigues. That same year, she played a series of avant-garde concerts directed by José Miguel Wisnik in Rio de Janeiro.
Soares scored a number of charts hits in Brazil throughout her career; some of the bigger hits include: "Se Acaso Você Chegasse" (1960), "Boato" (1961), "Cadeira Vazia" (1961), "Só Danço Samba" (1963), "Mulata Assanhada" (1965) and "Aquarela Brasileira" (1974).
A number of Soares's albums have also been re-released on CD in remastered editions: 1961's A Bossa Negra (containing her major hit of that year, "Boato") and 1972's big band backed Elza Pede Passagem (produced by Dom Salvador) being two of her most acclaimed releases. Elza Pede Passagem produced no major hit singles of the size of previous releases when originally released in Brazil; nevertheless, it is now considered a classic and representative of the "samba-soul" sound of the early 70s.
In 2002, her Do Cóccix Até O Pescoço album release earned her a Grammy nomination. The album received outstanding reviews in the music press and featured a who's who of Brazilian artists collaborating with her; Caetano Veloso, Chico Buarque, Carlinhos Brown and Jorge Ben Jor to name just a few. The release kickstarted a number of successful tour dates around the world. Two singles from the album were also promoted to Brazilian radio, "A Cigarra" and "Bambino", both were backed by promotional videos.
In 2004, Soares released her Vivo Feliz album to great acclaim. It contained the single, "Rio de Janeiro", a homage to her city of birth. While not as successful in sales as her previous release, the album carried on the theme of mixing samba and bossa with modern electronic music and effects. The album featured collaborations with groundbreaking artists such as Nando Reis, Fred 04 (former leader of mangue beat band Mundo Livre S/A) and Zé Keti.
More recently, Soares teamed up with Jair Rodrigues and a number of contemporary samba artists such as Seu Jorge for the old school flavoured Sambistas multi artist album which was released in 2009. In 2016, A Mulher do Fim do Mundo was released internationally with the translated title Woman At The End Of The World. She also had the honour of performing at the opening ceremomy of the 2016 Rio Olympics.