Kyle Lovett's night on the town started at The Ivy nightclub, and ended in an alley being strip-searched by police.
Officers questioned the Wests Tigers forward while he was sitting at the wheel of a black Mercedes Benz near The Star casino, in Pyrmont, about 1.20am on December 23.
Police pulled him over in an area known to be used for drug deals, and noticed he was "sweating profusely" and clenching his jaw, according to a statement of facts before Downing Centre Local Court.
They found white powder in the driver's seat and footwell, and the passenger's side footwell, before taking Lovett into an alcove to strip search him.
When asked if he had any drugs in his underwear, he said: "I'll be honest with you, I do."
Officers found a small bag of cocaine in his underpants, and charged him with possessing about 0.39 grams of the drug.
Police also found a blue and white MDMA capsule on the road under the car, but Lovett said "I don't touch that stuff."
He had a wad of cash on him, which he said was casino winnings.
Lovett, 23, appeared in court on Wednesday and pleaded guilty.
His lawyer, George Elias, told magistrate Janet Wahlquist it was Lovett's first offence, and he accepted full responsibility for his actions.
"I'd ask you to give him one chance," Mr Elias said.
"He comes before you as a person who is extremely remorseful."
Mr Elias said Lovett had to face the NRL integrity unit, and he didn't know what the future held for his career.
Ms Wahlquist said she took into account Lovett's youth, his clean criminal history, his remorse, and his early guilty plea.
She did not record a conviction, and handed down a six-month good behaviour bond.
The magistrate said everyone was treated equally in the court system, regardless of their occupation.
"Usually for young people I'm prepared to give leniency. Young people often experiment and do use a small amount of drugs.
"You should know that it's a danger, as it's quite commonly said, there's no quality control.
"I'm prepared to give you the benefit of leniency, it was a small quantity … you have an otherwise bright future."
Lovett is contracted with the Tigers until the end of 2017, but it was rumoured the club was attempting to force him out in a bid to ease salary-cap pressure.
He was supported by his parents and a team welfare officer in court, and thanked the magistrate as he left the courtroom.