Opponents of the project, including the City Club, a small civic organization; environmentalists; and the real estate developer Douglas Durst, had waged a legal battle in three different courts to stop the project. They argued that Pier 55 was developed in secret and without any consideration of alternatives for rebuilding Pier 54, the crumbling structure that the new pier was supposed to replace. They also questioned the need for another performance center in Manhattan, particularly one built over the river.

In the spring, both Mr. Cuomo and Mayor Bill de Blasio called Mr. Durst urging him to settle the dispute so that the project could move forward.

By September, the six-year saga appeared to be coming to an end. By all accounts, the Hudson River Park Trust was only days away from a settlement with the City Club and Mr. Durst.

But Mr. Diller had grown weary of the conflict as the cost of the project soared to $250 million from $130 million when it was publicly unveiled in 2014.

Mr. Diller and others blamed the escalating costs on the opposition.

The cost of most projects, whether new construction or a renovation, routinely increases as a development moves from concept to construction. Building on or over water is especially expensive because the wind, waves and marine animals are constantly wreaking havoc on any structure.

According to Mr. Diller, the attempt to revive the project came together in the last week. The governor called him and offered to try and put together a deal.

The governor’s pledge to complete the park and protect the estuary was key in getting opponents to drop their legal fight, said Richard Emery, the lawyer for the City Club. In the past, park officials have said it would cost $200 million to finish the remaining 30 percent of the park, but state officials did not pledge a specific figure, instead saying they would work with the trust and Mr. Emery’s clients to formulate a plan.