Few New York musical institutions under the tutelage of one individual have proved more enduring than the Opera Orchestra of New York and its music director, Eve Queler. This Thursday, OONY will celebrate Ms. Queler’s 100th performance with the company with a gala.

But while durable, OONY has not necessarily been stable. Last season, dark rumors about its financial security encircled the company, leading to a New York Times article questioning its future. But Ms. Queler took it in stride. The article triggered a “groundswell of support,” she said last week as she reminisced about OONY’s 40-year history. “The article upset some on the board, but it did the trick.”

For a woman who embarked on a conducting career in the 1960s, adversity is nothing new. After Ms. Queler was told that women were not welcome in the conducting programs at Juilliard and the Manhattan School of Music, she turned to the Mannes School of Music. And she studied privately with Joseph Rosenstock, despite his initial warning. “He told me I might conduct an orchestra in Podunk. But opera? Never.”

Ms. Queler was a pianist for the New York City Opera when she founded OONY, having also worked on concert operas for the Friends of French Opera, where she worked with tenor Nicolai Gedda. Mr. Gedda was a decisive force in OONY’s growth from a semi-student organization into a Carnegie Hall presence in 1972, with two French grand operas, Rossini’s “William Tell,” revived for him, and Meyerbeer’s “L’Africaine,” revived for Richard Tucker. “Singers wanted to do bel canto operas, and the Met wasn’t doing much,” Ms. Queler explained. “Most conductors aren’t interested in them because they can’t show off what they want to show off. Soon Caballé heard about me,” she said, referring to famed Spanish soprano Montserrat Caballé. “These singers took a chance on a green conductor and brought me to a place I could not have hoped to reach through normal channels.”

At OONY, Ms. Queler cultivated a sophisticated, slightly offbeat repertoire. Wagner’s sprawling early opera “Rienzi” is “a signature piece.” And she made a specialty of Russian and Czech operas, of which Smetana’s “Dalibor” was the first in 1977. “We bit the bullet and did operas in Czech, thanks to Yveta Graf,” she said, referring to a noted diction coach. Berlioz’s “Benvenuto Cellini” took the stage in 1983 with Mr. Gedda, and Strauss’s “Die Liebe der Danae” the same year, with Rosalind Plowright. Ms. Queler also mounted “anything with Caballé,” including “Parisina d’Este” (1974), “Gemma di Vergy” (1976), and “Aroldo” (1979), plus performances by the late Tatiana Troyanos, including Bellini’s “I Capuleti e i Montecchi” (1979), and Marilyn Horne in Rossini’s “Tancredi” (1978).

OONY’s success opened up new career opportunities for Ms. Queler, particularly in Europe, but OONY remained her anchor. During the years, she racked up her share of unique tales. She recalled taking the 24-year-old José Carreras to the throat doctor when his appearance in Verdi’s “I Lombardi” was in danger. And she learned the importance of lining up cover singers when Mr. Gedda called in sick for the initial “William Tell,” and the replacement ended up supplementing the score with an expletive.

In fact, the need for cover singers led her to create a veritable young artists program, always centered on the work being prepared for Carnegie. When OONY presented Bellini’s “La Sonnambula” in 1991, a work it repeated last week, Renée Fleming covered the title role. And a few years prior to that, audiences flocked to Lehman College when word got out that a young soprano, Aprile Millo, would sing Mathilde in “William Tell,” a role Ms. Millo was performing at Carnegie.

Currently, Ms. Queler is finding ways to bring rehearsals into the schools, having recently held a rehearsal of “Sonnambula” at Hunter College High School. “It’s a way to double up our resources,” she said. “And if I can find a sponsor to pay, it’s even better.”

And though OONY has, in fact, suffered financial unease, it has been fortified with new board members and Ms. Queler talks as if it clearly has a future, boasting that Olga Borodina will return in Rimsky-Korsakov’s “The Tsar’s Bride.”

After all, Ms. Queler said, the company needs to fulfill its role. “These operas need to be heard,” she said, “because the Met isn’t doing them.”