In the 1850, he partnered with Chicago attorney Edward Rucker in forming the North-Western Police Agency, which later became Pinkerton&Co, and finally Pinkerton National Detective Agency and is still in existence today as Pinkerton Consulting and Investigations, a subsidiary of Securitas AB.
In the 1850, he partnered with Chicago attorney Edward Rucker in forming the North-Western Police Agency, which failed. His older brother, Robert owned Pinkerton&Co, (A railroad Detective Agency) After Allan joined him, it was later known as the Pinkerton National Detective Agency and is still in existence today as Pinkerton Consulting and Investigations, a subsidiary of Securitas AB.