Secret Squirrel (voiced by Mel Blanc) serves as a secret agent, taking orders from his superior Double-Q (voiced by Paul Frees) of the International Sneaky Service. His designation is Agent 000. Secret Squirrel is assisted in his adventures by fez-wearing sidekick Morocco Mole (also voiced by Paul Frees impersonating Peter Lorre). The pair fights crime and evil enemy agents using cunning and a variety of spy gadgets, including a machine gun cane, a collection of guns kept inside Secret's trench coat, and a variety of devices concealed in his fedora (which he almost never removes).
- "Secret Squirrel" is a song on Marcy Playground's second album, Shapeshifter.
- Within federal law enforcement circles the slang term "secret squirrel" has been used to describe U.S. Secret Service Agents.
- In the military community, the term "Secret Squirrel" refers to the military's Special Operations community and the clandestine missions that they pursue.
- In the British private security industry, the term "Secret Squirrel" refers to a Store Detective, Loss Prevention Investigator, Profit Protection Investigator, Private Investigator or anyone who conducts investigations into criminal, dishonest or fraudulent activities.
- The term is often adopted by workplace managers who conduct disciplinary investigations, giving themselves delusions of grandeur, but this is wishful thinking.