“It is so rare to have the guidance of someone who is both an active performer and teacher of this repertoire, and we are honored to have him here with us today,” said Brian Zeger, the artistic director of Juilliard’s Vocal Arts Department and artistic administrator of the Metropolitan Opera’s Lindemann Young Artist Development Program, when introducing Mr. van Dam. This master class represented a new collaboration between Juilliard and the Met, bringing van Dam to work with master’s and artist diploma students from both the Vocal Arts and collaborative piano programs.

José van Dam continues to make his mark around the world with his powerful command, and sensitive interpretation, of opera and song repertoire. He finds in every work, according to The Boston Globe, “a point of intersection with his own life and experience.” Born in Brussels in 1940, van Dam entered that city’s conservatory at age 17, winning numerous prizes before making his debut in Liège as Don Basilio in Rossini’s The Barber of Seville. He went on to perform the role of Escamillo in Bizet’s Carmen at La Scala, Paris Opera, and Covent Garden. It was conductor Lorin Maazel who asked Mr. van Dam to record Ravel’s L’Heure Espagnole for Deutsche Grammophon, subsequently inviting him to join the Deutsche Oper in Berlin, where he sang his first leading roles. He sings regularly on the stages of the world’s major opera houses and festivals, including l’Opéra de Paris, Covent Garden, La Scala, Vienna State Opera, Deutsche Oper Berlin, Théâtre de la Monnaie in Brussels, Teatro Colón in Buenos Aires, San Francisco Opera, and the Lyric Opera of Chicago.

Many master classes become more about the guest artist than the students onstage, but from his first words, Mr. van Dam quickly established that his goals for the afternoon class focused on capturing the essence of a piece through specific textual and musical choices. These would, in turn, help to direct the musical intention of each singer.

First to sing was tenor Nicholas Coppolo, a member of the Juilliard Opera Center, singing Phidyle by Henri Duparc. His rich timbre and line filled the hall, supported by the sensitive touch of pianist Natalia Katyukova. As the audience applauded, Mr. van Dam rose briskly to the stage, giving Nicholas a bravo and friendly slap on the back as he crossed to the piano. But then he said, “You are not amoureux enough. Phidyle is your lover; we make again?” adding, “DuParc wrote without nuance, so from you, I want more text. For a singer, it’s often first the voice then the text, but you must understand the importance of the words.”

Next to the stage was soprano Devon Guthrie, singing Green and Il pleure dans mon coeur from Ariettes oublieés by Claude Debussy, set to poetry by Paul Verlaine. Debussy had a great affinity for this poetry and felt that his music worked best serving the text—poetry that was melismatic in style, as is apparent in Il pleure dans mon coeur. Green is a love song that begins with offerings from nature—fruits, flowers, and leaves—and ends with a falling into slumber.

Ms. Guthrie’s approach was rich and heartfelt, capturing the essence and spin of the French melodic line. Mr. van Dam thought her interpretation was beautiful but would benefit from greater anticipation of specific moments in the text and more focused choices, both in variety of color and in the movement of specific musical phrases. Her willingness to work was apparent, as she absorbed his suggestions with ease.

Master’s degree candidate and mezzo-soprano Cecelia Hall joined pianist Jonathan Ware onstage for Forêt from Le vieux coffretby André Caplet, followed by Poulenc’s Hôtel from Banalités, both well suited to her voice and rendered with rich musical interpretation and poise. “Take your time here,” said Mr. van Dam, in reference to Hôtel, which describes the lethargic joy of an afternoon alone with a cigarette. With Ms. Hall, his goal was similar to that of the other artists, with an emphasis on giving more attention to clarity of consonants and advice on how to color individual phrases.

Baritone Kelly Markgraf rounded out the afternoon with Chanson épique and Chanson romanesque from Don Quichotte à Dulcinée by Maurice Ravel. “Make it lighter. Remember, this is a Spanish dance,” Mr. van Dam advised, in reference to the first of the cycle, which describes the well-known character of Don Quixote, a parody of an idealistic and naïve knight who pursues an overweight and world-weary peasant girl he believes is the most beautiful woman in the entire world. “Make the words important and try to see what you sing, so that the people see it too,” said Mr. van Dam.

The afternoon ended all too suddenly, leaving us intrigued by his insight, charmed by his humbleness, and honored at having this unique opportunity for an inside view of masterful young artists and one legend at work.