sentences:  While studying at the Juilliard Opera Center, he sang the title role in "Idomeneo", Sam Polk in "Susannah", and Chevalier de la Force in "Dialogues of the Carmelites" under the baton of Julius Rudel.Subsequently, at San Francisco's Merola Opera Program, he performed Rodolfo in "La bohème" as well as the title role in "La clemenza di Tito" with Wolf Trap Opera.In 2004, O'Neill was the subject of a TVNZ, BBC documentary "The Understudy" about his contract at the Metropolitan Opera to cover Siegmund for Plácido Domingo in the Met's Otto Schenk production of "Die Walküre".