Rancatore studied violin and piano before studying singing with her mother at the age of 16 and later in Rome, with Margaret Baker Genovesi. At the age of 19 she debuted as Barbarina in Mozart’s The Marriage of Figaro at the Salzburg Festival. She returned to the Festival with Die Entführung aus dem Serail (1997, 1998), Verdi’s Don Carlo (1998; conducted by Lorin Maazel), Honegger’s Jeanne d’Arc au bûcher (2001), Hasse’s Piramo e Tisbe (2010; conducted by Fabio Biondi), and concerts at the Salzburg Mozarteum.
She sang for the first time in Italy in 1997 at the opening of the season at the Teatro Regio in Parma in L’arlesiana by Francesco Cilèa. At the age of 21 she debuted at the Teatro Massimo in Palermo as Sophie in Der Rosenkavalier and sang her first Olympia in Les contes d’Hoffmann at the Teatro Massimo Bellini in Catania. She has performed the role also at the Paris Opera, at the Royal Opera House in London, at the Zurich Opera, at the Massimo in Palermo, at the Opera in Rome, the Teatro Regio in Turin and Parma, the Toulouse Théâtre du Capitole, the Teatro Real in Madrid, La Scala in Milan, the Sferisterio di Macerata, the Chorégies d’Orange and the Vienna State Opera (2001).
She is also known for her portrayal of Gilda from Rigoletto, which she has performed in Melbourne, San Francisco, Las Palmas de Gran Canaria, Tokyo, Venice, Mexico, Vienna, Verona, Parma, Beijing, Florence, Zurich and London (concert version at the Barbican).
She debuted in the lead role in Lucia di Lammermoor in the Teatro Donizetti in Bergamo in the 2005/06 season, later doing a tour of Japan in this role, which included Tokyo, conducted by Antonino Fogliani. She sang the role again in the Oviedo Opera, in the Zurich Opera, the Teatro Comunale di Bologna, the Teatro Francesco Cileain Reggio Calabria and in the Teatro Comunale in Ferrara.
Another of her roles is Adina from L’elisir d’amore, which she debuted in Laurent Pelly’s production at the Bastille Opera in Paris and which she performed again in the Teatro Lirico in Cagliari and in La Fenice in Venice. She debuted the lead role in Delibes’ Lakmé, which she has sung in Palermo, the Campoamor in Oviedo and in the Bunka Kaikan in Tokyo. In December 2004, at the reopening of La Scala in Milan, she sang the role of Sémele in Salieri’s Europa riconosciuta, conducted by Riccardo Muti. She was invited to open the 2005/06 season at the Bologna Comunale in a new production of Ascanio in Alba and in October 2008 she made her debut as Elvira in Bellini’s I puritani in Palermo. In 2010 she debuted the role of Amina from La sonnambula in Las Palmas de Gran Canaria.
In concert she has also performed as a soloist in Rossini’s Petite messe solennelle in Paris, Mozart’s Great Mass in C minor in Salzburg, Mozart’s Requiem (Massimo, Palermo), and Pergolesi’s Stabat Mater (Paris, Radio France National Orchestra, conducted by Muti). She also participated in the opening concert of the 2003/04 season at La Scala and has sung with the Turin RAI Symphonic Orchestra and, in a gala alongside Bryn Terfel and the Royal Philharmonic Orchestra, London, as well as a Spanish tour with the Catania Massimo Bellini Philharmonic.
In 2011 she sang at the New Year’s Concert at La Fenice, at the Liverpool Philharmonic Hall, at Zurich Opera (Rigoletto), at Teatro Massimo Palermo (Lucia di Lammermoor), at Teatro greco di Siracusa (with Andrea Bocelli), at Sferisterio Opera Festival Macerata (Rigoletto[) and at the National Center for Performing Arts Beijing (Rigoletto).
2013 saw Rancatore’s return to the Salzburg Festival in a one-off TV-live/online production of Die Entführung aus dem Serail, staged (alongside vintage aircraft) in Hangar-7 of Salzburg Airport while conducted, without visual contact, in Hangar-8 by Hans Graf. The same year, Vienna State Opera billed Rancatore as Violetta in La traviata. In 2016 Rancatore sang Violetta the Royal Danish Opera.