Of Greek and Italian descent, Dalis grew up in San Jose, California. Dalis received her bachelor's degree from San Jose State College and master's degree in music education from Teachers College of Columbia University, and she received honorary doctorates from Santa Clara University and California State University.
Dalis was awarded a Fulbright scholarship and went to Europe to begin her singing career. She studied in Milan and gave her first performance of any kind at the Oldenburgisches Stadtstheater in Germany. This was so successful that she was offered a Fest 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 Stadtische Oper 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.
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. Everywhere, Dalis' acting went hand-in-glove with her singing. Erickson concluded that Dalis's debut was "one of the most exciting in recent seasons"
That was the first of 274 performances with the Met Opera company; it lasted through 20 seasons. She was particularly noted as Amneris in Verdi's Aïda, a part she sang 69 times at the Metropolitan. She was Brangäne when Birgit Nilsson sang her first Tristan und Isolde at the Met in 1959, Amneris when Leontyne Price debuted in Aïda at the Metropolitan in 1961 and Princess di Bouillon for Plácido Domingo’s Met debut in Adriana Lecouvreur. She also performed with soprano Leonie Rysanek frequently, most notably 17 performances of Die Frau ohne Schatten, as well as in Salome and Aida.
In 1961, Dalis appeared as the first American to sing the role of Kundry in Parsifal at the Bayreuth Festival. Her portrayal of this role was recorded in 1962 with Jess Thomas as Parsifal, Hans Hotter as Gurnemanz, and Hans Knappertsbusch conducting. This recording won the Grand Prix du Disc in 1964. In San Francisco, she sang the Nurse in Die Frau Ohne Schatten. and Ortrud in Lohengrin, among other roles. She performed in the gala to mark the conclusion of the career of Sir Rudolf Bing
One reviewer said of her Kundry:
Her broadcast portrayal is made memorable by the sensuous quality of her middle and upper voice…. she startles with the sheer beauty of her voice and her interpretive subtlety. The luscious timbre, with its seductive shimmer, contains its own magic...Her flexible phrasing and command of text bespeak a singer who inhabits her character to the fullest, achieving a fusion of musical and dramatic elements...Dalis owns a singular combination of vocal and interpretive gifts.
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. I have had colleagues who ceaselessly tried to convince the audience that they should be the one singing Isolde. Then everything goes wrong and nothing in the relationship works. But here, everything ran perfectly.
Fan appreciation also runs deep. Her home burned down in 1990 and she lost a lifetime’s collection of recordings and memorabilia. 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.
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. "This company was based on my two years in Oldenburg,” Dalis says. "In my time there, I sang nine major roles—it would have been 10 but I had appendicitis! And I thought, 'Why not find young talent and have them sing the big roles, rather than starting in the chorus and working their way up?'" As its chief officer, she led the company for its entire history, taking particular pride in its fiscal stability.
In keeping with her philosophy of encouraging young singers, with the support of an anonymous donor, Dalis established the Irene Dalis Vocal Competition in 2007, which is held in San Jose every spring. Ten finalists compete for $50,000 in cash prizes. 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.
Dalis was awarded the prestigious San Francisco Opera Medal in 1998. Her other credits include Principal Artist at the Metropolitan Opera, San Francisco Opera, Royal Opera House, Covent Garden, Bayreuth Festival, Chicago Lyric Opera, Berlin, Rome, Naples and others. Her awards include Fulbright Award, 1951; Richard Wagner Medallion, Bayreuth, West Germany, 1963; Tower Award, San José State University, 1974; Honored by the Board of Directors of the Metropolitan Opera Association on the occasion of her twentieth anniversary season, 1977; Woman of Achievement Award from the San José Mercury News and the League of Friends of Santa Clara County Commission on the Status of Women, 1983; Commendation from the Hon. John Vasconcellos, 23rd Assembly District, 1983; inducted into the California Public Educators Hall of Fame, 1985; Award of Merit from the People of the City of San Francisco, 1985; Honored Citizen of the City of San José, 1986; listed in Who's Who in America (since 1958); Who's Who in Opera (since 1971); and Who's Who in Music; Beautiful Minds Award recipient (2010). In 2013, she received the Cornerstone of the Arts awarded by the City of San Jose Arts Commission and the Career Award from the National Opera America Center.
In 1957, Dalis married McGraw Hill book editor George Loinaz who died in 1990. The marriage produced one daughter, Alida. Dalis has two grandchildren. Dalis died at the age of 89 in San Jose, California on December 14, 2014.