As the Saudi affair was being resolved, Mossley manager Bob Murphy offered O'Keefe a contract at the Northern Premier League club. In December 1976, he duly signed for Mossley after the Saudi club eventually agreed to release him from his contract. Howard Wilkinson was appointed as Mossley's manager in 1976, only for Murphy to return the following year. Wilkinson used O'Keefe as a left-back, though Murphy decided to play him an attacking midfielder due to his 'pace, power and eye for goal'. Under Murphy, the club won the Northern Premier League and Premier League Cup double in 1978–79 – this was the club's first significant success in seventy years. A part-time player, he also worked as a van driver for the "Manchester Evening News".