He made his Chicago debut in 1983 as The Priest in the company premiere of Lady Macbeth of Mtsensk and by 1988 had appeared there in Carmen, Arabella, and Die Frau ohne Schatten.
[2] His European debut came in 1985 when on the invitation of Bruno Bartoletti, he sang The Animal Trainer and The Athlete in Alban Berg's Lulu at the Maggio Musicale in Florence, roles he would later reprise in Chicago and at San Francisco Opera.
[4][5] Cowan made his Metropolitan Opera debut in 1990 on the opening night of the season as Schaunard in La bohème and went on to perform there as Guglielmo in Così fan tutte and in the title role of Don Giovanni,[4] a role he would sing many times in the opera houses of North America and Europe.
His other leading roles have included Bluebeard in Bartók's Bluebeard's Castle (Deutsche Oper in Berlin, Opera de Geneve, Melbourne, Liege, and the RAI National Symphony Orchestra in Turin), Escamillo in Carmen (Chicago, Toronto), Jokanaan in Salome (Miami, Minneapolis, Vancouver), and Nick Shadow in Stravinsky's The Rake's Progress (Spoleto Festival).
[6] Cowan was the artistic director of Lyrique en Mer, Festival de Belle Île in France.