"See also List of Los Angeles municipal election returns, 1963 and 1967

Cassidy was a friend of City Councilman Ransom M. Callicott and served five years as the councilman's field deputy; Callicott had been elected in 1955 to represent the Los Angeles City Council District 12, which in that year covered a downtown area bounded roughly by Venice Boulevard on the south, Sunset Boulevard on the north, Catalina Street on the west and Figueroa Street on the east.Callicott died in 1963, and Cassidy was appointed at the age of 59 by unanimous vote of the City Council on December 7, 1962, to succeed him until the April 2, 1963, primary election.