Both men were charged with conspiring to launder billions of dollars embezzled from 1MDB, and conspiring to violate the US Foreign Corrupt Practices Act (FCPA) by paying bribes to various Malaysian and Abu Dhabi officials.
A spokesman for Jho Low, who was charged in absentia at a United States court yesterday, said as noted in the indictment, the businessman held no formal position at 1MDB, nor was he ever employed by Goldman Sachs or the governments of Malaysia or Abu Dhabi.
The other banker has been arrested, while Mr Low remains at large. Leissner pleaded guilty, and Ng was arrested in Malaysia.
Low, a friend of Najib's stepson Riza Aziz, had no official role at 1MDB but had considerable influence over its dealings and was in frequent contact with Najib, U.S. authorities have said.
In a statement issued on his behalf by a public relations firm based in Sydney, Australia, Low who is also known as Jho Low, asked for the public to keep an open mind regarding the case until all the evidence comes to light as he believed that he would be vindicated.
Lawyers for Low and Leissner did not immediately return messages seeking comment. The banker, Andrea Vella, was put on leave in October, according to a person familiar with the matter.
The DoJ highlighted the alleged conspirators' attempts to secure Goldman's involvement in a share sale of 1MDB's energy assets.
Goldman has not yet responded to the indictments.
Prosecutors say Low, Ng, and Leissner conspired to launder the proceeds of fraud involving 1MDB through the US financial system.
Goldman acted as the primary bond underwriter for the fund. Other funds were used for the personal benefit of defendants, including purchases of luxury USA real estate and art. It has previously denied any wrongdoing.
Goldman provided an array of services to the fund, including helping it sell billions of dollars in bonds to investors, earning about US$600-million in fees for its work.
At least six countries, including Malaysia, the United States and Switzerland, have been investigating alleged thefts from 1MDB.
Since the election, Malaysian authorities have brought 38 charges against Najib.
Roughly $681m of that money is alleged to have ended up in the private bank accounts of Najib, who is facing 38 charges of corruption in an ongoing investigation into the 1MDB scandal.
Najib and Mohamad Irwan Serigar Abdullah, the former treasury secretary-general, pleaded not guilty to misappropriating government funds between December 2016 and December 2017.