Asgari was accused by a US court in 2016 of stealing trade secrets while on an academic visit to Ohio, but the 59-year-old scientist from Tehran's Sharif University of Technology was acquitted of charges in November.
The Iranian experts of materials science and engineering arrived in Tehran on Wednesday morning.
On Tuesday, Iran’s Foreign Ministry spokesman denied reports about a prisoner swap in the release of Asgari from a US jail, saying the Iranian scientist was released after being acquitted of charges.
He has been acquitted of bogus charges and let out of prison following the diplomatic consultations and efforts by the Iranian Interests Section in Washington, DC, and the Islamic Republic’s mission to the UN in New York, Mousavi had said.
Asgari told British newspaper The Guardian in March that the Immigration and Customs Enforcement agency was keeping him in a detention center in Louisiana without basic sanitation and refusing to let him return to Iran despite his exoneration.
The US agency database still listed Asgari as being detained in the state of Mississippi.