Throughout his childhood in Barcelona, Carreras's father, Josep Carreras i Soler, worked as a traffic policeman. He had originally been a French Teacher. However, he had fought on the Republican side during the Spanish Civil War, and when the Franco government came into power in 1939, he was no longer allowed to teach. 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. He was very close to his mother, who was convinced that he would one day be a great singer, and her death from cancer when he was 18 affected him greatly. In José Carreras: A Life Story, he said that "even now, every time I go on stage, I always, always, have a quick thought for her." In 1971 Carreras married Mercedes Pérez. They had two children: a son, Albert (born in 1972), and a daughter, Julia (born in 1978). The marriage ended in divorce in 1992. In 2006, Carreras married Jutta Jäger, but separated from her in 2011. Carreras's nephew, David Giménez Carreras, is a Conductor and Director of the Orquestra Simfònica del Vallès. He has conducted many of Carreras's concerts since the late 1990s as well as his opera performances in Sly at the Gran Teatre del Liceu in June 2000.
Carreras was born in Sants, a working class district in Barcelona. He was the youngest of Antònia Coll i Saigi and Josep Carreras i Soler's three children. In 1951, his family emigrated to Argentina in an unsuccessful search for a better life. However, within a year they had returned to Sants where Carreras was to spend the rest of his childhood and teenage years.
At the age of 8, he also gave his first public performance, singing "La donna è mobile" accompanied by Magda Prunera on the piano, on Spanish National Radio. A recording of this still exists and can be heard on the video biography, José Carreras – A Life Story. On 3 January 1958, at the age of 11, he made his debut in Barcelona's great opera house, the Gran Teatre del Liceu, singing the boy Soprano role of Trujamán in Manuel de Falla's El retablo de Maese Pedro. A few months later, he sang for the last time as a boy Soprano at the Liceu in the second act of La Bohème.
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 13 years, both in the recording studio and on stage. They later made a studio recording of La bohème for Philips Classics and can be heard together on over 12 other commercial recordings of both operas and recitals, predominantly on the Philips and Deutsche Grammophon labels.
During the 1970s Carreras's career progressed rapidly. In late 1971, he won first prize in Parma's prestigious Voci Verdiane competition which led to his Italian debut as Rodolfo in La bohème at the Teatro Regio di Parma on 12 January 1972. Later that year he made his American debut as Pinkerton in Madama Butterfly with the New York City Opera. Other major house debuts followed – the San Francisco Opera in 1973, as Rodolfo; the Philadelphia Lyric Opera Company in 1973, as Alfredo in La traviata; the Vienna Staatsoper in 1974, as the Duke of Mantua in Rigoletto; London's Royal Opera House in 1974, as Alfredo; the New York Metropolitan Opera in 1974, as Cavaradossi in Tosca; and La Scala, Milan in 1975, as Riccardo in Un ballo in maschera. By the age of 28, he had already sung the tenor lead in 24 different operas in both Europe and North America, and had an exclusive recording contract with Philips, which resulted in valuable recordings of several less often performed Verdi operas, notably Il Corsaro, I due Foscari, La battaglia di Legnano, Un giorno di regno and Stiffelio.
In its prime, Carreras's voice was considered one of the most beautiful tenor voices of the day. 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". This is particularly true of the middle range of his voice. Fraga also noted, as has Carreras himself, that even in his youth the high notes of the tenor range were always somewhat problematic for him, and became more so as his career progressed. Like his idol, Giuseppe di Stefano, Carreras was also known for the beauty and expressiveness of his phrasing and for his passionate delivery. These qualities are perhaps best exemplified in his 1976 recording of Tosca with Montserrat Caballé in the title role and conducted by Sir Colin Davis.
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. He also made full-length recordings of two musicals – West Side Story (1985) and South Pacific (1986) – both with Kiri Te Kanawa as his co-star. His 1987 Philips recording of the Argentine folk mass, Misa Criolla, conducted by its Composer, Ariel Ramírez, brought the work to a worldwide audience. Although many of Carreras's stage performances are available on video, he also ventured into film. In 1986, he portrayed the 19th century Spanish tenor Julián Gayarre in Romanza Final (The Final Romance) and in 1987, he started working on a film version of La bohème directed by Luigi Comencini.
The Daily Telegraph wrote of his 1984 Andrea Chénier at London's Royal Opera House: "Switching effortlessly from the lyric poet Rodolfo in La Bohème a few weeks ago to the heroic poet Chenier, the Spanish tenor's vocal artistry held us spellbound throughout." Of his 1985 performance in Andrea Chénier at La Scala (preserved on DVD), Carl Battaglia wrote in Opera News that Carreras dominated the opera "with formidable concentration and a cleverly refined vocal accent that imparts to this spinto role an overlay of intensity lacking in his essentially lyric tenor." However, Carl H. Hiller's review of the La Scala performance in Opera also noted that while in the quiet phrases of the score "he could display all the tonal mellowness of which this perhaps most beautiful tenor voice of our time is capable", he had difficulty with the high loud notes, which sounded strained and uneasily produced.
Following his own recovery from leukaemia, Carreras sought both to repay the debt he owed to medical science and to improve the lives and care of other leukaemia sufferers. On 14 July 1988, he established the Fundació Internacional Josep Carreras per a la Lluita Contra la Leucèmia (known in English as the José Carreras International Leukaemia Foundation) in Barcelona. The foundation, which publishes a tri-monthly magazine on its activities, Amigos de la Fundación, concentrates its efforts in four main areas:
In 1990 the first Three Tenors concert, took place in the Baths of Caracalla in Rome on the eve of the 1990 FIFA World Cup finals. 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. However, it and the subsequent Three Tenors concerts brought Carreras a fame that went far beyond the opera house. It is estimated that over a billion people around the world watched the television broadcast of the 1994 Three Tenors concert in Los Angeles. By 1999, the CD from the first Three Tenors concert in Rome had sold an estimated 13 million copies, making it the best-selling classical recording of all time. The early 1990s also saw Carreras serving as the Musical Director for the opening and closing ceremonies of 1992 Barcelona Olympic Games, and performing in a worldwide concert tour in tribute to his first singing hero, Mario Lanza.
The José Carreras International Leukaemia Foundation also has affiliates in the U.S., Switzerland, and Germany, with the German affiliate the most active of the three. Since 1995, Carreras has presented an annual live television benefit gala in Leipzig to raise funds for the foundation's work in Germany. Since its inception, the gala alone has raised well over €71 million. Carreras also performs at least 20 charity concerts a year in aid of his foundation and other medical related charities. He is an Honorary Member of the European Society for Medicine and the European Haematology Association, an Honorary Patron of the European Society for Medical Oncology, and a Goodwill Ambassador for UNESCO.
Carreras has received numerous awards and distinctions for both his artistic and humanitarian work. These include: Commander of the Ordre des Arts et des Lettres and Chevalier of the Légion d'honneur (France); Knight Grand Cross and Grand Officer of the Order of Merit of the Italian Republic (20 May 1996 and 3 April 1991, respectively); Grand Decoration of Honour for Services to the Republic of Austria (1999); the Cruz de Oro del Orden Civil de la Solidaridad Social from Queen Sofia of Spain, the Prince of Asturias Prize for Art (joint winner, 1991), the Grand Cross of Merit from the Federal Republic of Germany and the Gold Medal of the Generalitat of Catalonia (June 1984)
By the 2000s Carreras's recording and live concert repertoire had moved largely to art song, Neapolitan songs, the light classical genre, and 'easy-listening'. He has also increasingly performed and recorded with artists from outside the classical music world, such as Diana Ross, Edyta Górniak, Lluis 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.
On 23 February 2004, the Austrian Post Office issued a 1€ stamp to commemorate the 30th anniversary of his debut at the Vienna Staatsoper.
He has Honorary Doctorates from the University of Barcelona and Miguel Hernández University (Spain); Napier, Loughborough and Sheffield universities (United Kingdom); the Mendeleev Russian University of Chemistry and Technology (Russia); the University of Camerino (Italy); Rutgers University (United States); the University of Coimbra (Portugal); the National University of Music Bucharest (Romania); Philipps-Universität Marburg (Germany, 3 May 2006); University of Saarland (2012); the University of Pécs (Hungary) and most recently, Kyunghee University (Korea) and the University of Porto (Portugal).
Honorary Medal of the city of Leipzig on the occasion of his Leukemia Fundraiser for 2009 on 17 December 2009; awarded by the Mayor of Leipzig (unanimous decision of the town council of Leipzig).
In Spain the central plaza in Sant Joan d'Alacant bears his name, as do two theatres – the Auditori Josep Carreras in Vila-seca (near Tarragona) and The Teatro Josep Carreras in Fuenlabrada.