The former leader of a Haitian street gang was sentenced on Monday to 35 years in prison for his role in directing a gunrunning scheme that smuggled guns to Haiti using ransom money that had been paid for the release of American hostages, prosecutors said.

Judge John D. Bates of the U.S. District Court for the District of Columbia sentenced the former gang leader, Joly Germine, 31, of Croix-des-Bouquets, Haiti, in a Washington courtroom.

Mr. Germine, who was known as Yonyon as the leader of the 400 Mawozo gang in Haiti, pleaded guilty on Jan. 31 to a 48-count indictment that charged him with several crimes, including money laundering, smuggling and conspiracy to defraud the United States, the U.S. attorney’s office for the District of Columbia said in a statement on Monday.

The 35-year sentence does not address other charges of conspiracy to commit hostage taking that Mr. Germine also faces after the 400 Mawozo gang claimed responsibility in 2021 for taking 16 American hostages and one Canadian. The hostage-taking case, which Judge Bates is also overseeing, is to go to trial next year, court records show.

After the 400 Mawozo gang took the 17 hostages in the fall of 2021, the gang sought a ransom of $1 million for each hostage, prosecutors said. (The hostages, who were part of a missionary group visiting an orphanage in Port-au-Prince, were all released or managed to escape by December.) The gang then used some of the ransom money to buy at least 24 guns, including AR-15s and AK-47s, which were smuggled from the United States into Haiti, prosecutors said.

Attorney General Merrick B. Garland said in a statement on Monday that the money used in the gunrunning scheme had been “extorted from kidnapping American citizens.”

He said that the leaders of violent gangs in Haiti that terrorize American citizens to fuel their criminal activity “will be met with the full force of the Justice Department.”

Lawyers for Mr. Germine did not immediately respond to requests for comment on Monday evening.

Federal prosecutors had asked that Mr. Germine be sentenced to life in prison, according to a sentencing memo. Mr. Germine had asked for no more than 17 years and five months.

Three others have been sentenced in the gunrunning scheme, but face significantly less time in prison than Mr. Germine. Eliande Tunis, 46, of Pompano Beach, Fla., who was known as the “queen” of the gang, was sentenced on June 5 to 12 years and six months in prison for her role in the scheme, according to prosecutors.

Jocelyn Dor, 31, and Walder St. Louis, 35, who worked for Mr. Germine and Ms. Tunis, were also sentenced earlier this year, according to court records. Mr. Dor was sentenced to five years in prison, and Mr. St. Louis was sentenced to three years, prosecutors said.

Lawyers for Ms. Tunis, Mr. Dor and Ms. St. Louis did not immediately respond to requests for comment on Monday.

Mr. Germine had initially pleaded not guilty. During his trial, two dozen witnesses testified and evidence showed that he had overseen the purchase of the weapons by cellphone, according to prosecutors. Mr. Germine directed the three co-defendants to buy at least 24 rifles, handguns and a shotgun from a Florida gun shop, prosecutors said.

Mr. Germine changed his plea to guilty during the trial.

Ms. Tunis, Ms. Dor and Mr. St. Louis bought the guns in part by falsely stating that they were “not buying the firearms for another person, when in fact, they intended to ship and did ship the firearms back to Haiti for use by the 400 Mawozo,” according to court documents.

In 2021, the three shipped firearms and ammunition back to Haiti, smuggling some of the weapons by covering them up with “clothes, shoes and Gatorade,” court documents said. Some of the weapons were confiscated by the F.B.I. before they left the United States.

Court records outline call records, audio messages and text messages illustrating how Mr. Germine had overseen the purchase of the guns.

In one such message, Mr. Germine “admonished” Mr. St. Louis for failing to follow his instructions on how to purchase firearms and “praised” Ms. Dor for being able to follow “similar directions.” Ms. Tunis also reportedly took pictures of the weapons and sent them to Mr. Germine.