Born and raised in Vancouver, British Columbia, David studied at the School of Architecture at the University of British Columbia.  Upon graduation, David was retained by Hugh Shirley Architects and was mentored by him for the next four years.  David also worked with other Architects, such as Raymond Ching Architect and Douglas L. Massie Architect, until forming the firm of David S. Mah Architect in 1994.

David became a registered member of the Architectural Institute of British Columbia in 1992.  A joint partnership of firms between Douglas L. Massie Architect and David S. Mah Architect was formed to oversee two townhouse/apartment projects from 1993 to 1995.

During his time of working for others, David was involved in projects of varying use and size ranging from interior design projects to larger urban design projects. 

After the formation of his firm, David has continued to deliver projects of immutable design sensitivity of economy and taste.