Hembrow was married to Nathalie Stanley, whom he met while in Trinidad and Tobago filming The Last Island (1990).
Mark first stepped on stage at age 16 at La Boîte Theatre Company as Barnaby Tucker in The Matchmaker and then Sandy in Hay Fever and Apollo in Fetch Me A Fig Leaf the musical, all directed by Graham Johnson.
He also performed in Equus, School for Scoundrels, Savages, Jumpers, The Department, Hamlet and Fourth of July before heading to Sydney.
Mark returned home from the USA, and decided to have a break from acting for a number of years, in order to raise his family.
Recent guest roles on Australian television include The Straits directed by Rachel Ward and Old School starring Bryan Brown and Sam Neill by Matchbox Productions.