Born in Athens, baritone Tassis Christoyannis began piano lessons at the age of 9 and at 17 he joined the Athens Conservatory, where he studied singing conducting and composing. From 1995-1999 he was a member of the ensemble at the Greek National Opera in Athens.

Christoyannis will soon be heard as Germont in La Traviata in Genève, Nantes, and will also sing Figaro in Il Barbiere di Siviglia at the Vienna State Opera. Other future engagements include Posa in Don Carlo in Frankfurt, Renato in Un Ballo in Maschera in Tours, La Traviata in Glyndebourne, Taddeo in L’ Italiana in Algeri, Marcello in La Boheme at the Paris Opera.

In February 2012, he sang a well-received Macbeth in Bordeaux. The following April, he sang Silvio in Pagliacciand Figaro in Il Barbiere di Sivigliain Paris and in Genève in September.

In March 2011, he sang Ford in Falstaff in Nantes, and in May he was heard as Monfort in Les Vêpres Siciliennes in Genève. The following September he sang Valentin in Faustin Paris. In January 2010 he sang the leading role in a world premiere in Athens, then sang Don Giovanni in Budapest under the baton of Ivan Fischer. Also in 2010, he sang Oreste in Andromaqueby Grétry in Schwetzingen, Montpellier, and Nürnberg. He also sang Posa in Don Carlo in Frankfurt, and Figaro in Il Barbiere in Genève.

In January and February 2009, he sang the title roles in Ulisse and Pelléas et Mélisande in Düsseldorf, followed by Ford in Falstaff (V.Jurowski / R.Jones) at the Glyndebourne Festival, and Oreste in the revival of Andromaque by Grétry in Paris and Bruxelles. In December 2009, he sang Figaro in Il Barbiere in Rouen.

Between January and May 2007, he sang in Lucia in Düsseldorf, Fautszenen (Schumann) in Athens, Lucia in Tours, Hamlet and Don Giovanni in Düsseldorf. In September 2007 he was heard as Olivier in Capriccio at the Paris National Opera.  The following November he sang Enrico in Lucia in Amsterdam, and Falke in Die Fledermaus in Lausanne in December. In 2008, he sang Germont in Düsseldorf, Figaro in Il Barbiere at the Berlin State Opera, Alfonso in La Favorita in Montpellier, Posa in Don Carlos in Düsseldorf. He also notably sang Guglielmo in Così under Ivan Fischer in Las Palmas and Budapest.

In 2006, he sang the title role in Hamlet in Düsseldorf, then Ford in Falstaff and Enrico in Lucia di Lammermoor. In December he made his debut in Brussels at the Théâtre de la Monnaie as Germont in La Traviata. In 2005 he sang Il Ritorno di Ulisse in Patria in Düsseldorf, followed by Papageno, Posa in Don Carlos and Bajazet in Tamerlanoin Athens. He ended the year with a critically acclaimed Figaro (Barbiere) at the Staatsoper Berlin.

Beginning in 2000, as a leading baritone at the Deutsche Oper am Rhein in Düsseldorf, he sang: Posa in Don Carlos, Germont in La Traviata, Enrico in Lucia di Lammermoor, Conte in Le nozze di Figaro, Don Giovanni, Figaro in Il barbiere di Siviglia, Dandini in La Cenerentola, Taddeo in L´Italiana in Algeri, Silvio in I Pagliacci, Ulisse in Il ritorno d´Ulisse in patria, Guglielmo in Così fan tutte, Oreste in Iphigenie en Tauride, and Eugen Onegin.

As a member of Greek Opera house (1995-1999) he sang Belcore in L´elisir d´amore, Don Carlos in Ernani, Papageno Die Zauberflöte, Figaro in Il Barbiere di Siviglia, Guglielmo in Così fan tutte, and the title role in Eugen Onegin.

In 1993 he studied Italian repertoire in Cremona under the Italian baritone Aldo Protti. In 1994 he was awarded the Aldo Protti Golden Medal and in 1995 won "First Honorary Mention" at the Maria Callas International Singing Competition.

In-demand internationally he has given performances in, Hamburg, Pisa, Cremona, Mantova, Como, Brescia, Torino, Firenze, Montpellier Bonn, Mannheim, Strasbourg, Virginia, and at Carnegie Hall in New York.