At the Kaufman Music Center on the Upper West Side, Lydia Kontos has raised many millions of dollars, booked concerts, grown audiences, increased enrollment in programs and launched new ones, saved an organization on the brink of folding in the 1980s, attracted top classical musicians to teach, and once sewed an eighth grade flutist’s pants when they split just before a recital.

After nearly 40 years, Kontos is stepping down as executive director. In 1979, she joined what was then called the Hebrew Arts School for Music and Dance as a public relations consultant. Next Monday, she’ll receive the Kaufman Music Center’s Lifetime Achievement Award at its gala.

During her tenure, the center’s population has risen from 400 students to more than 3,000 in its Lucy Moses School (LMS) and another 500 in the Special Music School (SMS), a public school she founded that integrates music and academic study. A busy lineup of concerts, theater programs and performance series at Merkin Hall brings thousands of others into the building on a weekly basis.

“Lydia is tremendous,” said pianist Igal Kesselman, who is director of LMS and music director of SMS. “She has a vision and the strategic tools to implement it.”

The Hebrew Arts School was founded in 1952 by the late Tzipora Jochsberger, and moved to its present location on West 67th Street in 1978. Over four decades, divisions and major programs have been added, names have been changed, but the founding spirit of promoting Jewish culture and musical excellence has remained.

That Kontos is not Jewish has not been an issue. As pianist Orli Shaham, a member of the center’s board of directors, said, “Beyond deep respect for Judaism, Lydia has embraced all aspects of what it means to be Jewish.”

In an interview, Kontos told The Jewish Week, “The idea of being closed for Jewish holidays and Shabbat goes back to the beginning. The feeling was that no Jewish child, observant or not, should be prevented from participating in our programs.” She joked that she once ran into a board member on Broadway and had to explain to him that it was Shemini Atzeret, and that the center was closed.

More seriously, she added, “The idea behind the day of rest, for everyone, is a gift.”

Kontos grew up in Jackson Heights, Queens, and was a minority as a non-Jew among mostly Jewish classmates. Her own musical education began as a child taking piano lessons. She might have studied voice in college, but since she enrolled at age 15, administrators did not accept students her age into their voice program. Instead, she studied anthropology at Hunter, and worked as an assistant to legendary concert series director Omus Hirschbein at the college’s recital hall. “I learned about the possible from Omus. I learned to have nerve.”

She said that the story of the Hebrew Arts School in the 1980s was “a cautionary tale, but also a tale of dreams fulfilled.” After the building — a gift of Abraham Goodman and family — was completed on what she described as “a West Side Story backlot,” the organization fell on dire financial times, with the high costs of operating the building. Kontos fought against selling the assets and instead, based on what she calls her “common sense and many years of balancing a checkbook,” developed a business plan. With substantial gifts from new trustees Henry and Elaine Kaufman — for whom the center is named — and the Lucy Moses Fund, they invested in scholarships.

“The Kaufman Center is so unusual — so much music going on in one place – and none of it would exist without Lydia,” said Shaham. “She is incredibly creative, and also steadfast; she knows when an idea is good and will not quit until she figures out how to make it happen.”

Kontos speaks with pride of students. To them she is Lydia. Last year, the first class graduated from the new high school at SMS, with a 100 percent graduation rate, and all the students going on to college.

The flutist with the torn pants had been a scholarship student at SMS. Kontos and her colleagues helped get him into Frank Sinatra School of the Arts (SMS didn’t have a high school program then). While continuing studies at LMS, he had a master class with Sir James Galway, and has since gone on to a university music program on full scholarship and graduate studies at the New England Conservatory.

“We nurtured him and stayed with him until we knew he had wings,” she said.

“When you’re put in a situation where you are able to realize dreams that make a difference in people’s lives, you’re a very lucky person. I’m grateful for these years.”

Shaham added, “We are all, as citizens of New York, indebted to her.”