Martha’s Vineyard Museum executive director David Nathans will step down early next year, the museum announced Wednesday.

Mr. Nathans, who has led the museum for the past six years, plans to leave by the end of March 2016, a press release said. A search for a new executive director will begin immediately.

Reached by telephone Wednesday afternoon, Mr. Nathans said he is getting married on Saturday and eventually will leave the Island.

“My life changes in three days,” he said. “And looking ahead at where we are as an institution, I think there are some exciting things to attract a really good candidate next year.”

Hired in 2009, Mr. Nathans came to the Vineyard from Princeton, N.J., with a background in both museum management and business marketing. He took the reins of an institution that was struggling with its finances and also its public image on the Island. A previous executive director had resigned amid a foundering $35 million capital campaign.

During his tenure Mr. Nathans has raised visibility at the venerable Island museum, strengthening the core mission by substantially beefing up exhibits and programming, including education programs, and casting a new vision for the future. That vision includes relocating the museum from its current home in downtown Edgartown to a new campus in Vineyard Haven at the former marine hospital overlooking the Lagoon Pond. The museum bought the old hospital building in June 2011 from the St. Pierre family who had long used the property for a summer camp. An ambitious capital campaign to make the marine hospital project a reality has not been completed.

Mr. Nathans said he is confident that the project will see successful completion in the next year or two, and he said that makes it a good time for a change in leadership.

“I’ve had that fun in the early stages [of the marine hospital project] and I think someone else should have that fun in the middle stages,” he said. “So it made sense to give someone else an exciting chance and have the board see the best group of candidates come forward and not a limited group.

“It’s bittersweet for me . . . . I’d love to stay through it, but I’d like to be with my wife.”

“David Nathans’ dedication, energy and vision have provided the institution with a forward momentum so that now we can realistically think about a major transformation,” museum board chairman Elizabeth Beim said in the press release. “He has made the museum a significantly more valued and recognized leader in the Island’s day-to-day cultural life . . . . it is a comfortable moment in our institutional history for us to make this change.”

Mr. Nathans cited his considerable work expanding museum programs. “We have grown tremendously in our programming — in terms of its diversity from what might have been considered a historical society type of programming to broader art, history and cultural programming,” he said. “Whether through events or exhibits, we needed to broaden our audience and the way you do that is to have more kinds of programs.”

He had high praise for the museum staff. “The staff has been the leader,” he said. “My job has been to encourage, coach try to be a catalyst — they do all the work. The credit really is a shared credit. The terrific staff is another reason it feels comfortable . . . . the next person is going to have a team that’s humming. That’s also one of the most bittersweet things. It was hard when we told them today,” he said.

Mr. Nathans said he will help with the search for his replacement, a process he said will likely take about six months. He recently turned 65, and said he plans to move to New York with his wife Kate Hastings — and the next phase of his career. “I’m not retiring,” he said.

Last fall the museum was awarded a $500,000 challenge grant from the National Endowment for the Humanities, specifically to boost education programs at the museum. The grant must be matched by $1.5 million in private donations; Mr. Nathans said the money will go toward creating an education endowment, a first for the museum.

As for the marine hospital capital campaign, he said fundraising is “more than halfway there,” but he would not be specific about how much money has been raised or how much needs to be raised.

“It’s kind of a moving target . . . . what it is today may shift a little down the road,” he said. “Numbers are quiet and still being formed.”