[3] Sheppard was appointed as acting Government Architect with the Ministry of Works in February 1959, following the sudden death of Gordon Wilson, and fully assumed the role in May 1959.
According to Duncan Joiner, the last to hold the title of Government Architect, "Many of the government buildings of this period are elegantly simple in concept, and economical in their use of materials and services, reflecting a New Zealand architectural design response to stringent import controls.
It was a period of inventiveness, and during this time New Zealand engineers and architects established their international reputation for seismic design.
"[7] Sheppard produced the detailed architectural drawings of the Beehive, the executive wing of the New Zealand parliament, from the original concept designs by Scottish architect Sir Basil Spence,[8] who is quoted as having remarked "It is not a Spence building, it is a Sheppard Building.
[12] Among the buildings which Sheppard personally designed, collaborated on, or supervised the design of are: In 2021, the former Putāruru Post Office (1970) was the recipient of an "Enduring Architecture Award" in the New Zealand Institute of Architects (NZIA) Waikato Bay of Plenty Architecture Awards.