The American soprano, Kathleen Cassello, studied singing privately in Delaware with Dan and Nancy Gamble Pressley and won many competitions on the east coast, specifically the Austrian American Competition headed by Charlotte Shedd. It was this competition, which sent her to Salzburg in 1984 to study at the Sommerakademie from which she never returned to live in her home. She since won prizes in a number of the most prestigious singing competitions, including the Pavarotti, Puccini, Vinas, Viotti and Belvedere competitions.
After winning first prize in the Salzburg Mozart competition in 1985, Kathleen Cassello made her European debut as the Queen of the Night in Die Zauberflöte at the Hamburg Staatsoper and during the next three years sang the role in more than 200 performances in Austria, Germany, Russia and Swizerland.
From 1987 to 1989 Kathleen Cassello was engaged by the Badisches Staatstheater in Karlsruhe, where she built up a wide-ranging and extensive repertoire including Donna Anna in W.A. Mozart's Don Giovanni, Mimi in La Boheme, and the title role in Lucia di Lammermoor, in which she later enjoyed an outstanding success in performances with Alfredo Kraus at the Rome opera and in Seville. It was her intense dramatic presence (work with Giancarlo del Monaco in La Boheme, Il Trovatore, La Traviata and Lucia di Lammermoor) as well as her brilliant vocal technique, which first brought Cassello to the attention of the Marseille opera. After her well received debut as Manon in Massenet's opera in Metz, and a hugely successful Lucia di Lammermoor in Sao Paolo, Brazil and in the Nuits d'Ete in Marseille opposite Ramon Vargas, she was invited for the 1990-1993 seasons to make her debuts as Thais in Massenet's opera at the Marseille opera with Jose Van Dam, Michelangelo Veltri conducting and with Nicolas Joel directing and as Elvira in the Nuits d'Ete production of I Puritani. In 1991, she made her debut as Pamina inW.A. Mozart's Die Zauberflöte at the Liceo in Barcelona, opposite Francisco Araiza, and her husband, baritone, Renato Girolami. She debuted at the Bayerische Staatsoper in Munich and at the Zürich opera as Konstanze in W.A. Mozart's Entführung aus dem Serail and sang her first Leonore from Il Trovatore in Leipzig with Keith Olsen and Robert Overman under the stage direction of Giancarlo del Monaco. Cassello also sang Lucia in Malaga and in San Sebastian under the direction of Friedrich Haider and La Traviata in Oviedo under the direction of Bertrand de Billy.
After her Thais production with Nicolas Joel, Kathleen Cassello was invited to Toulouse to make her debut as Vitellia in Clemenza di Tito with Rockwell Blake and Martine Dupuy, conducted by Friedemann Layer and as Violetta in La Traviata with Franco Farina conducted again by Michelangelo Veltri. In August 1992, Kathleen Cassello took part in a marathon W.A. Mozart gala at the Arena di Verona where she came to the eye of the Italian theaters. In the fall of that year, she made her debut as Gilda in Rigoletto in Marseille opposite Leo Nucci and made her Italian theater debut in Treviso as Lucia, working with Leyla Gencer.
In 1993 Kathleen Cassello made her Rome opera debut with Alfredo Kraus, Giorgio Zancanaro and noted young conductor Daniel Oren as well as composer and stage director, Gian Carlo Menotti. This brought her to the attention of the opera La Fenice in Venice where she was engaged to sing Elettra in W.A. Mozart's Idomeneo as well as to the festival at the Choregies d'Orange. After a successful Konstanze in Avignon, she made her debut live on France 2, the national television, in the Choregies as Violetta in La Traviata with Roberto Alagna, Paolo Coni and conductor Michel Plasson. She then returned to Marseille for a new production of Lucia opposite Jean-Luc Viala and Renato Girolami, conducted by Tiziano Severini, and made her debut at the Opera de Bellas Artes in Mexico City as Gilda with Ramon Vargas.
Kathleen Cassello made her Teatro alla Scala debut as Gilda under the baton of Riccardo Muti in June of 1994. Continuing her close association with Italy and France, in 1994 she made debuts as Amina in La Sonnambula under the musical direction of Evelino Pido, as Giulietta in I Capuleti e I Montecchi under the baton of Bruno Campanella, and as Giunia in Lucio Silla in concert for Radio France in Montpellier conducted again by Friedemann Layer.
In 1995 Kathleen Cassello began the year in Nales as Donna Anna in Don Giovanni with Michele Pertusi under the baton of Salvatore Accardo and then made her debut in Tokyo in as Violetta. She sang a concert for Katia Ricciarelli in Biarritz for the music festival and then returned to Marseille as Konstanze and to the Choregies as Gilda, with Jean-Philippe Lafont and Roberto Alagna, conducted by Pinchas Steinberg. Teatro alla Scala invited her back for Lucia di Lammermoor with Vincenzo La Scola, and she ended her year with La Traviata in Geneva conducted by Lawrence Foster.
Other leading conductors with whom Kathleen Cassello worked include Christian Badea, Sylvain Cambreling, Carlo Rizzi (in Pesaro under the stage direction of Graham Vick), Peter Schneider, Stefan Soltesz, Leone Maggiera, Gunther Neuhold, Christoph Perrick, Marko Letonja and Lothar Zagrosek.
In January 1996, after a very successful South African debut appearance in two concerts with Luciano Pavarotti, Kathleen Cassello was engaged by the producer, Tibor Rudas, as one of "The Three Sopranos" for a series of concerts beginning in Los Angeles in September 1996 and continuing throughout Europe and South Africa. She continued her operatic performances, singing Donna Anna in Dallas's production of Don Giovanni with Leila Cuberli and a new production of La Sonnambula at the Rome opera under the stage direction of Pupi Avati, the noted film director. As well as her return to the Choregies d'Orange as Donna Anna opposite Ruggiero Raimondi and Ferruccio Furlanetto, and conducted by Jeffrey Tate, she also returned to Radio France in Montpellier for another concert performance as Elettra in Idomeneo, again under the baton of Friedemann Layer. At the Hamburg Staatsoper she performed Mimi in La Boheme and as Violetta. She also opened the season in Toulouse with her role debut in Charpentier's Louise opposite Gregory Kunde, conducted by Michel Plasson and directed by Nicolas Joel.
1997 brought a new series of "The Three Soprano" concerts in Budapest, Kosice, Atlantic City and Reno as well as a revival of the Lucia di Lammermoor from the Rome opera in Seville, again with Alfredo Kraus and Gian Carlo Menotti as stage director. Kathleen Cassello returned to Toulouse as Gilda opposite Tito Beltran, conducted by Maurizio Arena, and then to her third consecutive year at the Choregies d'Orange in a televised production of Lucia di Lammermoor with Francisco Araiza, conducted by Louis Langree. Cassello was invited to participate in a Hommage to Callas in Paris where she performed the Lucia Mad Scene and Addio del Passato from La Traviata. She sang a new production of La Traviata in Oviedo and then made her debut at the Teatro Teresa Carrena in Caracas as Lucia. In Karlsruhe she gave a gala Lucia performance and ended the year with a "The Three Sopranos" concert in Memphis.
A gala of La Traviata opposite Renato Girolami in Switzerland, began 1998, then her second orchestral concert in Durban South Africa, as well as her debut as Ein Donizetti's Roberto Devereux in Marseille, under the baton of Tiziano Severini. She returned to Hamburg for a concert of Chausson's Poeme de l'Amour et de la Mer conducted by Serge Baudo. This seemed to be becoming a concert year for Kathleen Cassello. She performed in Frank Martin's Golgothe in the Gewandhaus in Leipzig and in Berlin under the baton of Marcello Viotti, as well as performing Francis Poulenc's Gloria and cantatas from Ravel, also with Viotti. As well as “The Three Sopranos" concerts and a gala performance of Lucia in Karlsruhe with Renato Girolami, 1998 also brought Cassello's return to the Opera de Bellas Artes in Mexico City as Elettra in Idomeneo singing again with Francisco Araiza. Cassello could also be heard in the “The Three Sopranos" concerts in Aschaffenburg and Pretoria as well as in the Verdi Requiem conducted by Antonello Allemandi in the cathedral of Chartres which was televised on France 2.
1999 began with a gala Boheme in Karlsruhe opposite Vicente Ombuena and Renato Girolami. Kathleen Cassello made her debut as Violetta at the Teatro Colon in Buenos Aires after having performed the Verdi Requiem in Dresden under the baton of Gianluigi Gelmetti. After more "The Three Soprano" concerts, she returned to the Semperoper Dresden as Donna Anna in Don Giovanni with Bo Skovhus conducted by Friedemann Layer. In June Cassello made a special appearance with “The Three Sopranos" in concert with Luciano Pavarotti at Earl's Court and continued the "Three Soprano" tour in the USA and in August in Berlin. She then made her debut as Marguerite in Charles Gounod's Faust at the Opera in Marseille, operatic concerts in Durban and Lyon and performed Strauss' Four Last Songs in Tenerife.
Kathleen Cassello also been heard in recital in Philadelphia, PA, Wilmington, Delaware, at the Opera in Rome, in the music festival in Biarritz, Lyon, Valence, Marseille, and Chartres, and in concert in Avignon, Montpellier, Paris, Cape Town, Stellenbosch, Hamburg, Leipzig, Berlin, Pretoria, Durban and with "The Three Sopranos".
Kathleen Cassello's 1999-2000 season included Konstanze in Die Entfuehrung aus dem Serail and Donna Anna in Don Giovanni at the Semper Oper in Dresden, as well as her role debut as Maria in Donizetti's Maria di Rohan at the opera in Aachen. Her Lucia di Lammermoor in Tenerife was so successful that they asked her back for the next two seasons and her role debut as Liu in Puccini's Turandot in Marseille in November was highly praised by the critics. She made her role debut as Giselda in Verdi's I Lombardi in Marseille in March of 2001. In the Spring of 2002, she made her debuts as Norma in Salzburg and as Cio cio san in Marseille.
Kathleen Cassello was most noted for her portrayals of Lucia in Lucia di Lammermoor, Violetta in La Traviata and Gilda in Rigoletto due to her wide vocal range and the expressiveness of her vocal and dramatic presence.