He currently plays for Drogheda United, wearing the number 26 shirt. He plays primarily as a Midfield. His preferred foot is Left. His current market value is estimated at 100K €.

His most recent move was a Loan from Drogheda United to Shamrock Rovers on 2025-11-29.

Across 33 appearances in the Ireland Premier Division 2025, John O'Reilly-O'Sullivan registered 0 goals and 0 assists, while completing 7 key passes out of 223 total passes with a passing accuracy of 5.2.