A parts for money deal didn't work out for the Novato man.
He plead guilty in a Miami federal court to a single conspiracy count in a deal with prosecutors.
Keshari told the judge he had compromised himself by helping Iran obtain parts for aircraft including fighter jets and attack helicopters.
Prosecutors say Keshari and his company, Kesh Air International, acted as a go-between in the deals with a supplier based in Florida.
The parts were shipped first to the United Arab Emirates, and then to buyers in Iran.
The plea deal means Keshari faces a maximum of five years in prison.