It was not until after his term in the Parachute Regiment, serving in war-stricken Italy during World War II, however, that he was able to explore the field of urban landscape architecture. After working with the Royal Engineers during World War II, he travelled to America. He was admitted to the school of architecture at Harvard University's Graduate School of Design where he received professional degrees in both landscape architecture and city planning in 1949. After completing his education he returned to his homeland, intending to help rebuild a country ravaged by war. In Scotland he worked on housing and programs in "new towns", until he was contacted by Dean G. Holmes Perkins from the University of Pennsylvania. Dean Perkins wanted McHarg to build a new graduate program in landscape architecture at the University.