At first he studied piano and voice with Magda Prunera, the mother of one of his childhood friends, and at the age of eight, he also started taking music lessons at Barcelona's Municipal Conservatory.

At just eight years old, he also gave his first public performance, singing "La donna è mobile", accompanied by Magda Prunera on the piano, on Spanish National Radio.

Throughout his teenage years, he continued to study music, moving on to the Conservatori Superior de Música del Liceu and taking private voice lessons, first with Francisco Puig and later with Juan Ruax, whom Carreras has described as his "artistic father".

Although only a minor role, the few phrases he sang caught the attention of the production's leading lady, the eminent soprano and fellow Catalan, Montserrat Caballé.

In 1971, he made his international debut in a concert performance of Maria Stuarda in London's Royal Festival Hall, again with Caballé singing the title role.

Carreras's leading ladies during the 1970s and 1980s included some of the most famous sopranos and mezzo-sopranos of the day: Montserrat Caballé, Birgit Nilsson, Viorica Cortez, Renata Scotto, Ileana Cotrubaş, Sylvia Sass, Teresa Stratas, Dame Kiri Te Kanawa, Frederica von Stade, Agnes Baltsa, Teresa Berganza, and Katia Ricciarelli.

His artistic partnership with Ricciarelli began when they both sang in the 1972 La bohème at Parma and lasted for thirteen years, both in the recording studio and on stage.

[c] Of the many conductors he worked with during this period, the one with whom Carreras had the closest artistic relationship and who had the most profound influence on his career was Herbert von Karajan.

With Karajan's encouragement, he increasingly moved towards singing heavier lirico-spinto roles, including Aida, Don Carlos, and Carmen, which some critics have said were too heavy for his natural voice and may have shortened his vocal prime.

The 1980s saw Carreras occasionally moving outside the strictly operatic repertoire, at least in the recording studio, with recitals of songs from zarzuela, musicals and operettas.

[9] His 1987 Philips recording of the Argentine folk mass, Misa Criolla, conducted by its composer, Ariel Ramírez, brought the work to a worldwide audience.

However, he recovered from the disease after undergoing a gruelling treatment involving chemotherapy, radiation therapy and an autologous bone marrow transplant at the Fred Hutchinson Cancer Research Center in Seattle.

Following his recovery, he gradually returned to both the operatic and the concert stage, embarking on a tour of come-back recitals in 1988 and 1989 and singing with Montserrat Caballé in Medea (Mérida, Spain 1989) and in the world premiere of Balada's Cristóbal Colón (Barcelona, 1989).

The 1990s continued to see Carreras performing on the operatic stage in Carmen and Fedora and making role debuts in Samson et Dalila (Peralada, 1990), Verdi's Stiffelio (London, 1993), and Wolf-Ferrari's Sly (Zurich, 1998).

His final operatic performances at the Gran Teatre del Liceu, the opera house where his career began, were in Samson et Dalila (March 2001).

It was originally conceived to raise money for Carreras's leukemia foundation and as a way for his colleagues, Plácido Domingo and Luciano Pavarotti, to welcome their "little brother" back to the world of opera.

The early 1990s also saw Carreras serving as the Musical Director for the opening and closing ceremonies of the 1992 Barcelona Olympic Games, and performing in a worldwide concert tour in tribute to his first singing hero, Mario Lanza.

[13] He has also increasingly performed and recorded with artists from outside the classical music world, such as Diana Ross, Edyta Górniak, Lluís Llach, Peter Maffay, Udo Jürgens, Klaus Meine, Charles Aznavour, Kim Styles, Sarah Brightman, Vicky Leandros, Jackie Evancho, Sissel Kyrkjebø, Debbie Harry, Majida El Roumi, and Giorgia Fumanti.

Since 1995, Carreras has presented an annual live television benefit gala in Leipzig to raise funds for the foundation's work in Germany.

His mother, Antonia Coll i Saigi, ran a small hair-dressing salon, where, as a child, Carreras often sang to the customers in return for pocket money.

[27] The Spanish critic, Fernando Fraga has described it as a lyric tenor with the generosity of a spinto, having "a noble timbre, richly coloured and sumptuously resonant".