Kassim Tajideen owned Arosfran, a food import company, in Angola, and left the country after an international arrest warrant for financing and money laundering for the Shiite group Hezbollah was pending.
The businessman was arrested in Morocco in 2017 from where he was extradited to the United States, and was sentenced to five years in prison after pleading guilty before the US authorities.
According to the Associated Press news agency, a State Department official said that the US government had opposed Tajideen's motion for release on health grounds. Tajideen was designated a terrorist in 2009 and his assets remain blocked, the official added.
There were no immediate comments from the Lebanese authorities on the early release of Tajideen.
Lebanon's national news agency described Tajideen's arrival in Beirut, noting that the businessman used a small jet.
According to the National, a 64-year-old English-language United Arab Emirates newspaper, Tajideen was released because of health conditions and fear of coronavirus infections in prison.
Tajideen was convicted of conspiring with at least five other people to embezzle more than USD 50 million in transactions with US companies, in violation of the sanctions to which he was subject for his support of Hezbollah.
Tajideen pleaded guilty last December and agreed to hand over 50 million dollars to the authorities.
In March, a Lebanese military court ordered the release of a Lebanese-American detained in the country almost six months ago on charges of working for an Israeli-backed militia two decades ago.
The release of Amer Fakhoury has given rise to speculation that, in return, the early release of Tajideen could be granted.
Fakhoury, 57, who had been accused of murder and torture for decades in Lebanon, became an American citizen last year and now owns a restaurant in Dover, New Hampshire.
Separately, General Kenneth McKenzie, commander of U.S. Central Command, visited Lebanon on Wednesday, where he met with President Michel Aoun and senior political and defense officials.
The U.S. Embassy said McKenzie reaffirmed to Aoun the "importance of preserving Lebanon's security, stability and sovereignty" and the strong partnership between the U.S. and the Lebanese Armed Forces.