Markham returned to the stage after an 11 year absence in the 2016 Showbiz Christchurch production of Evita as part of the ensemble.

His association with Showbiz began in 1973 at age 11 when he performed in Oliver!. With over 30 Showbiz shows to his name, highlights include: the Baker in Into the Woods, Gerald in Me and My Girl, Grantaire in Les Misérables, Doc in 42nd Street and as Che understudy in the 1991 production of Evita.

A lawyer by profession, Markham is a Life Member of both Showbiz and Musical Theatre New Zealand (MTNZ), the President of Showbiz Christchurch, as well as being Honorary Solicitor for MTNZ, Entertainment Technology New Zealand Incorporated and all the New Zealand musical theatre consortiums.