Brother of Crystal Palace and England shot-stopper Sam, the former Manchester United, Fleetwood Town, Sunderland, St Johnstone and AFC Fylde man joined the Silkmen in the summer.
He arrived from Dubai-based Gulf United for an undisclosed fee and was widely tipped to be the club's new number one following their promotion to the Northern Premier League.
However, he found himself behind Connor O'Keefe in the pecking order after the opening few weeks of the season, and the arrival of young Norwich City goalkeeper Dylan Berry on a short-term loan deal has further limited his potential game time.
In total, he made nine appearances for the club.
A club statement read: "Macclesfield FC can confirm that goalkeeper Max Johnstone will be leaving the football club.
"Johnstone made four clean sheets during his time at The Leasing.com Stadium and last featured against Sandbach United in the Cheshire Senior Cup.
"Everyone at Macclesfield FC would like to thank Max for his efforts and wish him all the best for the future."