[1] Jones came to prominence in 1964 when she stood in for Leontyne Price as Leonora in Verdi's Il trovatore at the Royal Opera House, Covent Garden.

Her career then developed rapidly, and she met with success as Aïda, Leonore (in Fidelio), Desdemona (in Otello), Elisabeth (in Don Carlos), Donna Anna (in Don Giovanni), Cio-cio-san (in Madama Butterfly), Lady Macbeth (in Verdi's Macbeth), Santuzza (in Cavalleria rusticana), Octavian (in Der Rosenkavalier), Médée (in the Italian version) and Tosca.

Jones's large-scaled, powerful dramatic soprano voice, unusually robust vocal stamina, stage presence and acting abilities were widely admired.

Starting from the 1990s, other than the aforementioned parts, she went on to sing Widow Begbick (Mahagonny), Ortrud (in Lohengrin), the Woman in Arnold Schoenberg's Erwartung, the Kostelnicka (in Jenůfa), the Woman in Poulenc's La voix humaine, Ruth (in The Pirates of Penzance), Gertrud (in Hänsel und Gretel), the Kabanicha (in Káťa Kabanová), Herodias (in Salome) and Klytämnestra (in Elektra), the last five being mezzo-soprano roles.

[4] Jones made roles that exemplify the Wagnerian or heavy dramatic soprano fach, such as Brünnhilde, Isolde, Elektra, the Dyer's Wife and Turandot, part of her core repertoire, and performed them throughout the 1980s and 1990s.

[5] and Die Frau im Schatten – which are inspired by real historical characters, namely, Malvina Schnorr von Carolsfeld and Pauline de Ahna (wife of Richard Strauss).

In February 2008 she returned to the Mezzo-soprano repertoire singing the role of Herodias in Stephen Langridge's production of Richard Strauss' Salome at Malmö Opera in Sweden.

Ein Haus der Kunstmusik, directed by Sven Holm at the 2012 Munich Opera Festival, playing Cosima Wagner.

Jones makes a guest appearance in Quartet, a film by Dustin Hoffman, based on the comedy by Ronald Harwood about several retired opera singers planning to put on a concert to celebrate Verdi's birthday.