In 1953, Simmonds was part of the Canadian Contingent during the Coronation of Queen Elizabeth II in England. In 1957, he moved to Calgary Subdivision as a Criminal Investigator. In 1966 he moved to Burnaby, British Columbia as Sub-Inspector, but transferred to Victoria in 1971 to work in the staffing and personnel department. Three years later, he was promoted to Superintendent and charged with commanding the Victoria Subdivision. In 1976, Simmonds was promoted from Chief Superintendent to Deputy Commissioner of Administration in Ottawa. On September 1, 1977 he was appointed Commissioner of the RCMP.