Max is the eldest of three sons to Paul and Theresa Reinhart. His younger brothers also play hockey: Griffin was a first round draft pick of the New York Islanders in 2012, and youngest brother Sam plays for the Buffalo Sabres having been drafted by them in the 2014 NHL Entry Draft. The three brothers played with and against each other throughout their junior careers, as Sam was a teammate of Max's on Kootenay's championship team while the pair opposed Griffin, who was a member of the Edmonton Oil Kings. Reinhart is the only one of the brothers who was not drafted in the first round of the NHL Entry Draft.