The expanded concourse offers sweeping views of the airport, upscale food and shopping options and increased seating.
The facility was also celebrated Friday for what it replaces: a now-decrepit terminal built by Pan Am in 1960.
Kennedy Airport is still the primary gateway to the U.S. It saw 13.1 million inbound international passengers last year, more than any other American airport, according to U.S. Customs and Border Protection.
Delta carries about 2.1 million of those arriving international passengers at JFK, more than any other carrier, according to the Port Authority, the airport's operator.
Delta CEO Richard Anderson said his customers "and the residents of New York now have the international hub facility that they expect and deserve." Travelers will appreciate both the big and small touches in the new facility. The 346,000-square-foot concourse houses local restaurant favorites like Blue Smoke and Shake Shack. Meanwhile, 75 percent of seats at the gates have access to electric outlets.
A 2,000-square-foot rooftop deck offers sweeping views of the runways and airplanes. But it is part of a new Delta Sky Club, accessible only to members or passengers flying international business class.