This was so successful that she was offered a contract in Oldenburg and remained there for two years between 1953 and 1955, making her professional debut there in 1953 as Princess Eboli in Verdi's Don Carlo.
She then moved to the Berlin's Städtische Oper[1] where her performance in Janáček's Jenufa led to an offer from The Metropolitan Opera, where she debuted in 1957, again as Eboli, to great applause.
[2] One New York City reviewer, Raymond Erickson, wrote: Her expert vocalism and musicianship were immediately apparent in the "Veil Song", which Dalis sang better than I have ever heard it sung.
In the tricky ensemble with Carlo and Rodrigo in the Queen's gardens, she was just as impressive, and her sweeping, almost torrential handling of O don fatale won her a genuine ovation from the capacity audience.
She performed in the gala to mark the conclusion of the career of Sir Rudolf Bing[6] One reviewer said of her Kundry: Her broadcast portrayal is made memorable by the sensuous quality of her middle and upper voice….
[7]The eminent Birgit Nilsson said of her collegial intelligence: Irene Dalis was wonderful to interact with: active, alert, but at the same time solicitous, as Isolde’s servant must be.
Unbeknownst to her, a former student quietly reassembled unauthorized recordings of her performances at the Met, San Francisco, Rome, and Bayreuth, and gave them to her as a gift.
[9] After retiring from the Met in 1976, Dalis returned to her hometown in California, where San Jose State University offered her the position of Professor of Music.
There she developed the Opera Workshop program, which began turning out so many career-level graduate singers that she decided to form the Opera San Jose in 1984, a professional company which hires young singers on a multi-year contract basis, allowing them to perform principal roles in the company's four annual productions.
IDVC finalists have gone on to significant careers; for instance, Audrey Luna (2009) has sung at the Met, The Santa Fe Opera, Tanglewood, and the Spoleto Festival.