Alexandru Agache was born in Cluj, Romania where he studied voice at the Cluj Conservatory of Music.
In 1979 he made his professional operatic debut at the Cluj Opera as Sharpless (Madama Butterfly) and in 1983 he was awarded First Prize in the Lucca International Singing Competition. This led to his debut in western Europe in Livorno, Italy in Don Giovanni.
Since 1988, when he made his debut as Renato (Un Ballo in maschera), Alexandru Agache has appeared with the Royal Opera House Covent Garden in London in roles such as Enrico (Lucia di Lammermoor), Simon Boccanegra, Rigoletto, Nabucco and Amonasro (Aida), Miller (Luisa Miller), and Gusmano (Alzira). He returned to the Royal Opera in 2001 as Jago (Otello).
Other European engagements included appearances at La Scala, Milano in L 'Elisir d'amore, Lucia di Lammermoor, Don Carlos, at the Teatro Comunale, Florence in Aida, Lucia di Lammermoor, Simon Boccanegra and Macbeth, at the Opera National de Paris Bastille in Un Ballo in maschera, Simon Boccanegra, La Traviata and Rigoletto, at the Grand Theatre de Geneve with Simon Boccanegra, at the Hamburg State Opera in Don Carlos, La Traviata, II Trovatore and Macbeth, at the Deutsche Oper Berlin as Andrea Chénier and at the Vienna Staatsoper in II Trovatore, Lucia di Lammermoor, La Bohème and Un Ballo in maschera. In 2000 he gave his debut at the Arena di Verona, in La Forza del destino and Nabucco.
The artist made his American debut in 1992 at the Houston Grand Opera in II Trovatore and appearances with the Lyric Opera of Chicago included La Traviata, Simon Boccanegra and Nabucco and, in 2000, Rigoletto.
At the Metropolitan Opera, New York, where Alexandru Agache made his debut in 1999, his roles included Simon Boccanegra, II Trovatore and Aida. He performed once again in Un Ballo in maschera in 2001.
In 1999 he made his debut at the Teatro Colòn, Buenos Aires, as Jago (Otello).
Alexandru Agache has appeared in concerts throughout Japan and Europe, and has been accompanied by orchestras like the Berliner Philharmonischer Orchester conducted by Sir G. Solti. He has recorded many of his roles for release on CD and Video.