Lesage is very active on the Montréal music scene: he was responsible for programming at the Société des concerts alternatifs du Québec, and a member of the SMCQ’s artistic committee from 1990 to 2011. Additionally, from 1987 to 1995 he was also a columnist for Radio-Canada’s “Musique actuelle”. In 1997 and 2008, he was guest editor at Circuit — Musiques contemporaines, a North American journal of 20th century music. Since 2005 he has been a member of the journal’s editorial board.
From 1995 to 2009, Jean Lesage was a regular guest composer and teacher at the Rencontre internationale de musique nouvelle at Domaine Forget. Since 1999 he has been a professor of composition and orchestration at McGill University’s Schulich School of Music.
Among fifty or so compositions to date are: Mare fecunditatis (1986) for piano (CAPAC prize 1987); Trois apparitions au désert (1988) for mixed choir and full orchestra (Robert Fleming Prize, Canadian Music Council 1988); Le sentiment océanique (1989) for eight instruments, commissioned by the Ensemble contemporain de Montréal, presented in Paris at the Unesco International Rostrum of Composers (1995); Les sensations confuses (1993) for chamber orchestra, commissioned by the Nouvel Ensemble Moderne (NEM), premiered in Strasbourg at the Musica 93 festival; Les représentations surannées (1998) for orchestra, commissioned by the Orchestre symphonique de Québec; Portrait of a Sentimental Musician in a Distorting Mirror (2000) for violin and piano, commissioned by the CBC; Quatuor à cordes I (2001), Quatuor à cordes II (2002), Quatuor à cordes III (2005) composed for the Quatuor Bozzini; Les mécanismes multiples de l’ivresse et de la nostalgie (2004) for full orchestra, commissioned by Radio-France and Radio-Canada; Le projet Mozart (2006), commissioned by Trio Fibonacci and Beatitudines (2011), commissioned by the Montréal Symphony Orchestra.