Tom, Dick or Harry Origin:
The origin of the phrase is unknown although it is very old, the oldest known citation is from the 17th-century English theologian John Owen who used the words in 1657.
Owen told a governing body at Oxford University that "our critical situation and our common interests were discussed out of journals and newspapers by every Tom, Dick and Harry."
Pairs of common male names, particularly Jack and Tom, Dick and Tom, or Tom and Tib, were often used generically in Elizabethan times.
For example a variation of the phrase can be found in Shakespeare’s Henry IV, Part 1 (1597): "I am sworn brother to a leash of Drawers, and can call them by their names, as Tom, Dicke, and Francis."