"I cared about music long before I cared about literature," James Merrill remarked in 1968. In fact, he knew exactly the point he began caring about music: when he was eleven-years-old, he was taken for the first time to the Metropolitan Opera House. The impact on his aesthetic education was immediate, profound, and endured throughout his career as a poet. His work is filled with references to music, both high and low. An operatic emotional intensity and keen attention to the musical textures of language via sophisticated metrical effects are consistently apparent in his poetry.

Merrill speculated that it was the emotional expression in opera, without any apparent attention to the words themselves, which inspired his interest in the form. His passion for opera compelled him to study French art songs, where he discovered that the lyrics, though more intelligible to him than those he'd heard at the opera, "...made no demands on the intelligence. It was only the extreme beauty of the musical line that was spellbinding." Finally, Merrill credits his introduction to German art songs as forging a meaningful connection between music and sung words, which in this case were often canonical poems, such as works by Shakespeare and Goethe. He explained, "By then, a way of uttering a line to have it make real sense, real human sense, had come into my musical education."

Merrill returned over and over to the theme of music throughout his substantial oeuvre. For example, the poem "Matinées" chronicles that first trip to the opera, taking in Das Rheingold, accompanied by a Mrs. Livingston, to whom the poet addresses a thank you letter in the final lines:

Dear Mrs. Livingston,
I want to say that I am still in a daze
From yesterday afternoon.
I will treasure the experience always-

My very first Grand Opera! It was very
Thoughtful of you to invite
Me and am so sorry
That I was late, and for my coughing fit.
I play my record of the Overture
Over and over. I pretend
I am still sitting in the theater.

In "The Victor Dog" (dedicated to Elizabeth Bishop), Merrill deeply imagines a day in the life of the eponymous trademark dog who listens gingerly to his master's voice booming from the horn of a Victrola phonograph. Merrill listens in:

Does he hear? I fancy he rather smells
Those lemon-gold arpeggios in Ravel's
"Les jets d’eau du palais de ceux que s’aiment."

He ponders the Schumann Concerto's tall willow hit
By lightning, and stays put. When he surmises
Through one of Bach's eternal boxwood mazes
The oboe pungent as a bitch in heat...

Regarding his own artistic process, Merrill considered his attention to art songs as a study in poetic tone. With his ear attuned chiefly to the sound of words, and the space between them, his compositional method was something akin to musical phrasing. "Whenever I reach an impasse working on a poem," he said, "I try to imagine an analogy with musical form; it usually helps." He cited the example of his poem "An Urban Convalescence" to illustrate his point: "’An Urban Convalescence’ is in the form of an Introduction and Allegro. In between comes a trill (on the word ‘cold’), an organ point (following ‘self-knowledge’), then the rhymes, the quatrains begin, in 4/4 time, as it were. Need I say how subjective this all is?"