William A. Pinkerton was the son of Allan Pinkerton, the entrepreneur who started the famous Pinkerton Detective agency in 1850, a private company with a reputation for being one of the most reputable law enforcement and crime detection forces in the country. Along with his younger brother Robert, William joined the family business as a clerk and rose to the rank of detective.
When Allan Pinkerton died in 1884, William and Robert took charge and continued their father’s vision for the agency, developing innovative crime-solving techniques, building an extensive collection of mug shots, and newspaper articles about wanted outlaws, and creating criminal histories on known offenders—practices that would later be adopted by the FBI. When the notorious robber known as The Missouri Kid blasted a bank in Union County, William had the foresight to pair his headstrong, street-smart detective, Charles Schumacher with the introverted, desk-jockey crime analyst, George Dougherty for a manhunt that would take many a twist and turn. Though no longer family-owned, the Pinkerton Agency today is a leader in security services.