Méhul was the greatest French symphonist before Berlioz and an important and prolific composer of opéras comiques. His musical style came out of Gluck's tradition of opera and Haydn's and early Beethoven's tradition of choral and instrumental writing. Méhul went beyond these influences, though, particularly in the realm of orchestration. His use of large forces and novel and striking effects anticipated Berlioz. The more colorful aspects of his instrumentation were always a result of the drama of the opera and never gratuitous. Méhul also developed certain other techniques such as the reminiscence-motif, which was to have a great influence on Weber and, later, Wagner. His harmonies could also be striking and unusual, but were generally less effective on a larger scale, where he remained quite conservative.
Méhul's only important teacher was Jean-Frédéric Edelmann, with whom he began studies in 1779. During the next decade, he produced two sets of piano sonatas and taught keyboard for a living. There is almost no other music surviving from this period to chart Méhul's early development. It was likely that he wrote much, though, for his first surviving opera, Cora (1786), is assured and well written. His next opera, Euphrosine (1790), however, literally made him famous overnight. Adrien (1791), never performed until 1799 for political reasons, and Stratonice (1792) followed. In the latter, Méhul created an intentionally antique style to capture the setting of the drama, a particularly romantic technique. The comedy Le jeune sage et le vieux fou (1793) was Méhul's last opera for many years to be unaffected by the impending political crisis in France. The remaining operas of the 1790s, Horatius Coclès (1794), Mélidore et Phrosine (1794), Le jeune Henri (1797), and Ariodant (1799), all contain political overtones and a "republican" message. During this period, Méhul also composed numerous anthems and instrumental works for the Institut National de Musique. This activity eventually brought him to Napoleon's notice, for whom he composed several works after 1800, including the opera L'irato (1801) and the Chant national du 14 juillet 1800, an important forerunner of Berlioz's Requiem.
Méhul turned to a series of minor comedies over the next years. The only important opera to emerge from this decade was Joseph (1807), probably his greatest. After this, Méhul turned to symphonic composition for a brief time, producing two extraordinarily successful works in 1808-09, and a series of Napoleonic cantatas (1810-1811). His opera Les amazones (1811) failed, however, and Méhul, disenchanted with the fall of the First Empire and the reorganization of the Conservatoire, produced no other major works until the successful La journée aux aventures in 1816. Although Méhul's works are seldom performed today, his influence on Berlioz, Beethoven, Mendelssohn, and Weber was profound, and he stands as one of the most important composers of the early Romantic movement in France.