He currently plays for Peterborough United, wearing the number 23 shirt. He plays primarily as a Defender. His preferred foot is Left. His current market value is estimated at 150K €.

His most recent move was a Loan from Enfield Town to Peterborough United on 2024-10-31.

Throughout the English Football League One 2025-2026, Harley Mills featured in 14 matches, averaging 1.4 tackles, 0.9 interceptions, and 3.9 clearances per game, while blocking 0.3 shots per game.