Devlin made his Metropolitan Opera debut in 1978 as Escamillo in "Carmen". His other performances at that venue have included "Hänsel und Gretel" (as Peter), "Les contes d'Hoffmann" (as the Villains, opposite Plácido Domingo), "Die Fledermaus" (as Dr Falke), "Bluebeard's Castle" (with Jessye Norman), "Salome" (as Jokanaan), "Samson et Dalila" (as Abimélech), "Faust", and "Wozzeck" (as the Doctor), altogether singing 229 performances in over thirty years with the Met. He has also appeared with companies in Chicago, Amsterdam, Salzburg, Verona, Madrid, London ("Salome" at Covent Garden), Paris, Prague, Los Angeles (Don Pizarro in "Fidelio", with Karan Armstrong), San Francisco ("Il prigioniero"), Santa Fe (Figaro, Count Almaviva, Don Giovanni, Onegin),etc.