Between 1934 and 1951, he undertook part-time architecture studies, before switching to town planning studies, while working as a draftsman at AGL, the Commonwealth Department of the Interior, Commonwealth Department of Works and Housing, and the Cumberland County Council.
[1] The Menzies Government established the National Capital Development Commission (NCDC) in 1958 and, in early 1959, appointed Harrison its first Chief Town Planner.
Harrison devised the 'Y plan',[2] adopted by NCDC in 1967, which allowed for the expansion of Canberra consistent with the preservation of the open character of a city separated by bushland.
[3] "Peter believed strongly that large city centres were inefficient creations of speculative development," Neutze wrote.
"[3] Harrison was awarded a life fellowship of the Royal Australian Institute of Architects in 1971, which he resigned in 1990, in protest at the RAIA ACT Chapter's position on Canberra's development.