San Francisco Ballet has a vibrant new artistic director: the celebrated Spanish dancer Tamara Rojo. And the company has had a relatively strong recovery from the pandemic, with ticket sales recently approaching pre-Covid levels.

Now San Francisco Ballet has received a groundbreaking gift: It announced on Thursday that it had secured a $60 million contribution from an anonymous donor, the largest in the company’s 91-year history and one of the biggest ever to an American dance company.

“It was, for me, an enormous surprise,” Rojo, who joined the company in 2022, said in an interview. “The impact is immeasurable.”

The vast majority of the gift, $50 million, will be used to bolster the company’s endowment, currently valued at about $108 million, and to help finance the creation and acquisition of new works. The remaining $10 million will be used to help cover operating costs in Rojo’s first few seasons.

Rojo said the donation would allow the company to achieve its aim of creating modern classics.

“It’s a gift of new creativity — a gift of the lifeblood of what a ballet company is and has always been,” she said.

San Francisco Ballet, with a budget of about $55 million, hopes the gift will help the company move beyond a series of challenges. The pandemic brought financial strains — ticket sales fell to about $18 million in the fiscal year that ended in June 2022, down from about $22 million in the year that ended in June 2019. Sales have recovered more recently, reaching about $21 million in the fiscal year that ended in June.

And subscriptions, which have traditionally been an important source of revenue, have continued to decline, as they have for many cultural organizations, to 6,118 so far this year from 7,784 in 2019. While favorites like “The Nutcracker” continue to draw crowds, and story ballets have been popular, some mixed-repertory programs have struggled to surpass 50 percent attendance. (The company performs at the War Memorial Opera House in San Francisco, which has more than 3,100 seats.)

The troupe has also been grappling with leadership churn. Last year, San Francisco Ballet’s executive director, Danielle St.Germain, stepped down after only a year in the position. She was replaced by Arturo Jacobus, who is serving on an interim basis. The company hopes to name a permanent leader by the fall.

Alison Mauzé, chair of San Francisco Ballet’s board, said in an interview that the gift, which came together over the last two months, would be transformational for the company. Still, she said it would not “fully protect the company from the challenges of the day.”

“It remains critical that we expand our audience and ensure that the meaning and importance of ballet become clear to the next generation,” Mauzé said. “Tamara Rojo’s leadership and vision are brilliant, but this will also require increasingly strong support from our community and serious investment across the operations of the company.”

San Francisco Ballet hopes it can experience a revival under Rojo, who previously served as the artistic director of the English National Ballet, helping to raise that company’s international profile. (She was a principal for English National Ballet and before that a star at the Royal Ballet.) Rojo said she wanted to commission more works that connect to social issues and to “continue to enrich the art form and to continue to make it an alive art form.”

This season is the first she has programmed. Its opener, “Mere Mortals,” a meditation on artificial intelligence, was a collaboration between the choreographer Aszure Barton and the electronic music producer Floating Points. The work, a world premiere, garnered critical acclaim and nearly sold out, drawing a large number of new audience members. Encore performances are planned for April.

Rojo said the gift was an investment in her goals.

“I felt an enormous wave of gratitude that there would be so much trust already in my vision and my ambitions that I have on behalf of San Francisco Ballet,” she said. “For me personally it’s a huge encouragement that I am going in the right direction, that my vision is the right vision.”