was born in Boulogne Billancourt, France on 24 September 1959. In 1978 he entered the Conservatoire National Supérieur de Musique in Paris, studying with Ivo Malec, Claude Ballif, Pierre Schaeffer, and Guy Reibel, graduating with three Premier Prix. Meanwhile, he followed classes with Olivier Messiaen, Franco Donatoni, Betsy Jolas, Jean-Claude Eloy, and Iannis Xenakis. In 1993 he was awarded the Villa Médicis residency in Rome for two years.
His compositional output, about seventy works to date, includes symphonic, vocal, electronic, acousmatic, and chamber music. He has received many commissions, notably from the French Ministry of Culture, Radio France Philharmonic Orchestra, Southwest German Radio, IRCAM, Les Percussions de Strasbourg, Ensemble intercontemporain, Ensemble Court-Circuit, Nouvel Ensemble Moderne de Montréal, Avanta Ensemble, Ensemble 2e2m, Ensemble Sillages, Ensemble Orchestral Contemporain, INA-GRM, Sixtrum, Ensemble Ictus, Festival Musica, Ensemble BIT 20, Koussevitsky Foundation, San Francisco Contemporary Music Players, Ensemble Athelas, Orchestre National de Lorraine, Orchestre Philharmonique de Nice, CIRM, INTEGRA, and many others.
His music is widely performed at various European festivals and by international orchestras such as Donaueschingen, Radio France Présences and Agora in Paris, Venice Biennale, Bath Festival, Festival Musica (Strasbourg), Stockholm ISCM, Barcelona Festival, Musiques en Scènes (Lyon), Manca (Nice), Bergen Festival, Ultima (Oslo), Tage für Neue Musik (Zurich), BBC Symphony Orchestra, Tonhalle Orchester, BBC Scottish Symphony Orchestra, Philharmonia Orchestra, Czech Philharmonic.
He has received many prizes and awards, including the Prix Hervé Dugardin, Best Contemporary Musical Creation 1996 for D’aller, SACEM Prize, André Caplet and Nadia and Lili Boulanger Prizes from the Academy of Fine Arts (Institut de France), Salabert Prize for Apocalypsis and Arthur Honegger Prize (Fondation de France) for his overall production. In addition, Philippe Leroux writes articles on contemporary music, teaches composition at Berkeley University, Harvard, Grieg Academy (Bergen), Columbia University, Royal Conservatoire in Copenhagen, Toronto University, Fondation Royaumont, IRCAM, American Conservatoire in Fontainebleau, Conservatoire National Supérieur in Paris and Lyon, Domaine Forget (Quebec), Georgia Institute of Technology in Atlanta, Tchaikovsky Conservatoire at Moscow.
From 2001 to 2006, he taught composition within the Cursus d’Informatique Musicale at IRCAM. In 2005 and 2006, he was professor at McGill University within a Fondation Langlois programme. From 2007 to 2009 he was composer-in-residence at Metz Arsenal and Orchestre National de Lorraine, and in 2009–11, visiting professor at Université de Montréal. Since 2011, he has been Associate Professor in composition at the Schulich School of Music, McGill University. He is currently composer-in-residence at Ensemble MEITAR in Tel-Aviv.

Major works (since 1995): D’aller, concerto for violin and 16 instruments (1995), Image à Rameau for four MIDI controllers (1995), AAA for large ensemble (1996), Souffles for wind quintet (1996), Ma belle si tu voulais... for voice (1997), M for two pianos, two percussions and electronics (1997), De l’épaisseur for accordion, violin and cello (1998), M.É., acousmatic work (1998), Un lieu verdoyant – Hommage à Gérard Grisey for voice and soprano saxophone (1999), Einsamkeit for voice and 14 instruments (1999), Plus loin for orchestra (1999–2000), SPP for saxophone and piano (2000), 3 bis, rue d’insister for quintet (2000), Les uns for three percussionists (2001), Rheumics for six percussionists (2001), De la vitesse for six percussionists (2001), L for choir (2002), VOI(REX) for voice, six instruments and electronics (2002), m’M for orchestra (2003), Airs for saxophone and percussions (2003), Du souffle for saxophone quartet (2003), Pour que les êtres ne soient pas traités comme des merchandises for 12 voices, orchestra and electronics (2004), Pour... for 12 voices, 16 instruments and electronics (2005), Apocalypsis: Dévoilement for four voices, 16 instruments and electronics (2005–6), De la texture for large ensemble (2007), De la disposition for orchestra (2007–8), L’unique trait de pinceau, concerto for saxophone and orchestra (2008), Pourquoi for four voices and orchestra (2009), Ama for piano (2009), Objets trouvés ... poses, acousmatic work (2009), Envers symphonie for orchestra (2010), Cinq poèmes de Jean Grosjean for six voices (2010), ... Ami...Chemin...Oser...Vie for large ensemble (2011), Extended Apocalypsis for four voices, 16 instruments, electronics and video (2011), Dense... englouti for piano (2011), Le cri de la pierre for bagpipe (2011), De l’itération for six percussionists (2012), Ailes for baritone and 15 instruments (2012), Total solo for large ensemble (2013).