The charges against Joseph Manuel Hunter were made in a 37-page indictment released by U.S. Attorney Preet Bharara.
Hunter, 48, was among six people arrested Wednesday in Thailand, The Bangkok Post reported.
Also named in the indictment were Timothy Vamvakias, German nationals Dennis Gogel and Michael Filter, and Polish national Slawomir Soborski.
Filter and Soborski have yet to be arrested.
The indictment charges Hunter recruited the four men in 2012 to be "contract killers" as part of a conspiracy to import large quantities of cocaine into the United States.
During that time, the men conspired to kill a U.S. drug enforcement agent and a confidential informant in Africa, the indictment says.
Deputy Thai National Police Chief Somyot Pummanmuang described Hunter as a "leading drug lord."
Somyot said Hunter was wanted for drug smuggling, trafficking and other international crimes.
The other suspects -- two British citizens, a Slovak, a Filipino and a Taiwanese national -- were arrested separately. They were not named in the Friday indictment and were held on separate charges.
All are expected to be extradited to New York, Somyot said.
"This group was considered to be a big network that spanned many countries" in Southeast Asia, the official said.
A federal court in New York issued a warrant for Hunter's arrest July 17, said Priewphan Damapong, an adviser to the chief of the Narcotics Suppression Bureau. Authorities canceled his Thai visa Sept. 19.
Hunter was arrested at the Phuket Country Club after agents with the U.S. Drug Enforcement Agency pointed him out to Thai officers.