Ritchie established his own company at the age of 21, "the first in Australia to manufacture heavy-duty electrical switchgear". He later formed partnerships with British and American companies, allowing him to "employ thousands of workers in four states". In 1934, he became general manager of Noyes Bros Pty Ltd, a Sydney-based manufacturer of radio sets and accessories. He eventually became the company's chairman and managing director, and also chaired the Australian subsidiary of Crompton Parkinson. Ritchie served on the New South Wales Electricity Advisory Committee from 1935 to 1946. During World War II, he was state business administrator of the Department of Munitions, for which he was knighted in 1951.
