The 17-year-old has impressed so far with the U18 Development side this season who are currently unbeaten in all competitions and through to the semi-finals of the Scottish Youth Cup.
Previously at Fulham FC and Spartans, Mack has celebrated his 18th birthday later this month and is the latest Hibs Academy youngster to pen a new deal, alongside brothers Oscar and Jacob McIntyre and his fellow defender Josh McCulloch.
Speaking on news, Academy Director Steve Kean commented:
"Mack is a commanding centre-half who has a fantastic physical presence and is very good at anticipating danger.
"On top of that, he is improving technically day on day and is very calm in possession of the ball."