Michael Riordan was born in Dooks, County Kerry, Ireland and emigrated to San Francisco at the age of eighteen. His first job was helping to clean up the rubble of the San Francisco earthquake of 1906, followed by railroad construction work in the Mojave desert. He later worked for an uncle, Michael, who ran a small grocery in the outer Mission District. He married Mary "Mollie" Mahoney, a childhood friend from Glenbeigh, County Kerry and they had four children: Catherine "Kay", John "Jack", Patricia "Pat", and Edward "Ed". He joined the San Francisco Police Department in 1913 as a patrolman after ranking fifth on the department's entrance exam. Thereafter he placed first or second on every promotional list and was made captain in 1925. He took leave from the department during World War I and become a sergeant major of the 55th Engineers. Riordan earned a master's degreein law in two years attending night school, became a lawyer and the department's legal advisor, drafting many sections of the Police Code. While a Captain, Frank Egan gave himself up to Riordan near 28th and Vicente and Riordan escorted Frank Egan to the police station. In 1940, he was appointed deputy chief and in September of 1947 he was appointed San Francisco's Chief of Police. At the start of his tenure, he denounced conditions at the old Hall of Justice on Kearney Street as, "...a monument to the last century's treatment of the accused." Riordan organized the San Francisco Auxiliary Police of civilian defense in World War II and established a program fostering closer ties between the San Francisco and Los Angeles Police Departments. His tenure lasted until a new mayor took office. After serving as chief, for a short time he became law partners with Vince Hallinan, representing Harry Bridges. Later he partnered with James C. Purcell, who represented many of the Japanese Americans who were interned and was appointed Assistant Attorney General for the State of California. He was also president of the Federation of Municipal employees and the United Irish Societies. He also served on the national board of the Ancient Order of Hibernians and was the Grand Marshall in the St. Patrick's Day Parade. He also became a director of the First San Francisco Bank. Riordan died after a six-week stay at the French Hospital on December 4, 1967, and is buried at Holy Cross Cemetery in Colma, California.
