Alexandros Markeas studied piano, chamber music, and theory at the Athens Conservatory. Starting in 1987, he undertook further study with Alain Planès (piano), and, from 1992, composition studies with Guy Reibel, Michaël Levinas, Laurent Cuniot, and Luis Naon, at the Paris Conservatoire (CNSMDP), graduating with highest honours in piano, counterpoint, and composition. In 1997-98, he participated in the IRCAM Cursus (IRCAM’s composition and computer music course), during which his work Penser/Classer was premiered. In 1998, he attended the first European Music Academy of the Aix-en-Provence International Festival, where he composed music for the ballet Rondo notturno (jardin secret). From 1999 to 2001, he was a resident at Villa Medici, and from 2005 to 2007, was in residence with Musiques Inventives in Annecy, in association with the Savoie Conservatory. A string of other artistic residencies followed: Quartz (Brest National Theatre) in 2008, Évreux National Theatre in 2011, Metz Arsenal/Orchestre National de Lorraine from 2014 to 2016, Rencontres Départementales de Musique de Chambre d’Ivry-sur-Seine in 2016-17, Les Détours de Babel Festival in Grenoble in 2017, Rueil-Malmaison Conservatory (in the suburbs of Paris) in 2018, and the Monaco Spring Arts Festival in 2019. In 2021, he was in residence at the International Music Festival in Besançon.

His catalogue comprises instrumental, vocal, and electroacoustic works which have been performed by ensembles such as Ensemble Intercontemporain (Exponentielles [1995]), Itinéraire (Modulor [1995]), Habanera Quartet (Anamnesis [1997]), Radio France Philharmonic Chamber Ensemble, Alter Ego, Court-Circuit (Les hommes le dimanche [2000]), Ensemble Modern, Arditti Quartet (Apostaseis [2001]), Percussions de Strasbourg (Time Ballet [2005]), TM+ (Archipelago [2009], Trois voyages [2010], and Citoyenne Insolente [2014]), Les Éléments (Medea Cinderella [2010]), Musicatreize (Dionysos, le vin, le sang [2010] and Wall Street Lullaby [2013]), Orchestre Nationale de Lorraine (Sea is History [2016]), and the Zahir Quartet (Voices of Black Earth [2016]).

Always endeavouring to enrich his work through contact with other artforms (text, theatre, visual arts, architecture), he has composed a number of scenic works, including Remarques sur les couleurs (1997), Narcisse (2006), and Trois voyages (2010), as well as music for video installation: Symphonie diagonale (2008). He also creates works involving improvisation, and draws upon Greek traditional musics, as in Taximi (2003), as well as those of other cultures. His catalogue also includes a number of pedagogical pieces, including Les oiseaux (2000), La querelle des muses (2002), and Le retour du loup (2010-11).

In June 2021, his work Music of Choices was premiered at the Pompidou Centre as part of ManiFeste.

Alexandros Markeas has taught generative improvisation at the Paris Conservatoire (CNSMDP) since 2003. He was awarded the SACEM Hervé Dugardin Prize in 2001, the Critic’s Prize in 2006 for his music for the play Le Cas de Sophie K, and the SACD “New Talent Prize” in 2009 for his opera, Outsider. In 2020, he was awarded the SACD Music Prize and in 2023 the SACEM Grand Prize for contemporary music.