Astorino has been complaining for years about Playland's impact on the county budget.
"It's hard to make the case that an amusement park is an essential service" when revenues are down, he said at the news conference. But he also said, "Saving Playland has been a priority for me since the day I took office."
He said the county will get $4 million up front and hopes to save $18 million by paying off the park's debt, which had been accumulating, in 12 years.
He stressed that the county will continue to own the land during the expected 10-year management agreement.
"We're not getting rid of any parkland," he said.
But he said a new business plan was needed because attendance had fallen from 1 million a year in 2005 to 433,000 this year.
"We want to take it from a 90-day use with one season to a year-round destination," he said.
Astorino, a Republican, said some aspects of the deal will require approval from the Democrat-dominated county Legislature. Majority Whip MaryJane Shimsky said the Legislature "has a lot of questions to be answered before public parkland is signed over to anyone. ... We want to make sure it stays a park everyone can use."