A Darien busboy arrested for selling marijuana out of the Post Road restaurant where he worked was sentenced to 18 months in prison on Thursday at the Stamford courthouse.

Namgyao Kelsang, 30, of Mansfield Avenue, sold marijuana to an undercover police officer on two occasions earlier this year and was arrested on charges that included conspiracy to sell marijuana, possession of marijuana and possession of marijuana with intent to sell.

Kelsang pleaded guilty to a charge of sales of a controlled substance before Judge Richard Comerford. After he gets out of jail, he will spend three years on probation. However, his public defender, Lisa Stevens, said she expected that in New York, where Kelsang is on probation from a second-degree robbery charge, would already be violating his probation in that state for the Darien arrest.

According to his arrest affidavit, police received word from an informant on Jan. 16 that a busboy at the Post Road restaurant Steam, formerly Wild Ginger, was asking kids if they want to buy marijuana. That night, two plainclothes officers went to the restaurant and asked Kelsang, a Nepalese national, for a lighter. The officer mentioned that he heard they had good “weed” at the restaurant. Kelsang pulled the officer into a bathroom and said he would be able to “take care of him.”

Later that night, the officer met Kelsang and Kelsang’s friendin front of the Darien Social restaurant on the Post Road and exchanged $60 for 3.5 grams of marijuana, the affidavit said. A few days later Kelsang brought the police officer over to his home and sold him 2.5 grams of marijuana for $60, the affidavit said.