After nearly 25 years as the director for the Institute of Contemporary Art in Boston, Jill Medvedow has decided to move on.

“When I started, we were striving to be marginal,” she said in a phone interview about the institution she has led since 1998. “We graduated to scrappy, we got to nimble and now we are quite solid.”

Medvedow, who informed ICA Boston staff members on Wednesday morning that she was leaving at the end of next year, said that she was proudest of giving artists like Jeffrey Gibson and Amy Sillman their first major museum exhibitions. A search for her replacement is already underway.

“I think Jill Medvedow is one of the most underrecognized, underestimated and under-celebrated museum leaders,” said Helen Molesworth, who served as the museum’s chief curator from 2010 to 2014. “And if she was a man, she would have been feted all over the place for her accomplishments.”

The museum that Medvedow joined in the late ’90s included a small set of galleries tucked inside a former police station in Boston’s Back Bay neighborhood; it lacked a permanent collection and received just 10,000 annual visitors. In 2006, she relocated the organization into a $62 million facility by the harbor designed by Diller Scofidio + Renfro, inaugurating one of the city’s first new museums in a century. More expansions followed, including a second location across the water. The ICA Boston said it now receives about 310,000 annual visitors.

Molesworth and other former employees described Medvedow as a boss who held high expectations of her staff.

“Her drive to champion contemporary art changed how Bostonians came to understand and to accept difficult art into their daily lives,” said Paul Ha, who directs the nearby Massachusetts Institute of Technology’s List Visual Arts Center. “I will miss having Jill as a colleague and it is undeniable the impact she had.”

During a period when contemporary art became a financial instrument of speculation, the museum director attempted to steer her institution toward civic values, and fun initiatives. Her projects have included educational programs for some 6,000 teenagers and a competition where expert divers jump from the museum roof some 90 feet into the harbor below.

Although she is putting the museum behind her, Medvedow said it was unlikely that she would leave the art world entirely. “I don’t think I am capable of real retirement,” she said. “But I will say that I have walked through the world with ICA eyes, and I’m now interested in seeing it through my own eyes.”