Walsh was arrested on September 26 after allegedly disobeying a police direction to move on from a nightclub at Surfers Paradise.
Upon being taken back to Surfers Paradise police station, police allegedly found a small quantity of cocaine on the 19-year-old.
Walsh pled guilty to the charges in court and has been placed on a good behaviour bond and fined a total of $400, but avoided any other punishments or a conviction being recorded.
According to The Daily Telegraph, the court heard Walsh swore at police and acted in a disorderly manner.
The youngster admitted to his actions the following day in a club press conference, and spoke to the media following Monday's court proceedings.
"I'm really embarrassed and ashamed of what happened," Walsh said as he departed court.
"I'm going to repay my family and friends. The club, the fans all stuck behind me and I'll work hard to bounce back from this to make sure it never happens again."
The NRL also slapped Walsh with a two-game ban, meaning he won't be available until Round 3 in the 2022 season. He was also previously fined $5000 by the competition.