Micah Alleyne, 24, was arrested and charged with second-degree murder, criminal possession of a weapon and reckless endangerment relating to the September 2015 shooting, police said Friday.
Police say Gabay was caught in the crossfire between rival groups and was shot in the head at an event before the West Indian Day Parade in Brooklyn, New York. He was pronounced dead nine days later.
Alleyne was seen on surveillance video running away from the shooting, police told CNN affiliate NY1.
“His name surfaced early. A lot of informants, or information, I should say, came forward naming him early on,” NYPD Chief of Detectives Robert Boyce said, according to NY1.
Alleyne’s attorney, Edward Friedman, did not respond to CNN’s request for comment.
Police plan to make more arrests in the coming days, CNN affiliates reported.
Cuomo hailed the arrest in a statement, describing it as “a major step forward in the pursuit of justice for Carey’s family and loved ones.”
In the months after Gabay’s death, police began to release photos of people wanted for questioning and posted a reward of $22,500.
Two months ago, police asked the public to help identify four individuals — three men and one woman — who were possibly connected to the shooting.
“As I have said from the beginning, we are determined to get justice for Mr. Gabay and his family. And we will continue to press forward until we hold everyone responsible for his death accountable,” Brooklyn District Attorney Ken Thompson said in a statement.
Gabay, a 43-year-old lawyer, was serving as deputy counsel for Empire State Development when he was killed.
Raised in public housing in Bronx, New York, Gabay graduated from Harvard University and joined Cuomo’s administration in 2011, first in Albany and then in New York.
On May 15, which would have been Gabay’s 44th birthday, the city renamed a stretch of Clinton Avenue in Brooklyn in his honor.