His voice was created by actor Mel Blanc, heavily patterned after the character of Senator Claghorn, a blustering southern politician who was a regular character on the Fred Allen radio show. Senator Claghorn was created and voiced by radio comedian Kenny Delmar. Foghorn Leghorn also used a number of Claghorn's catch phrases, like "That's a joke, son". The references to Senator Claghorn was obvious to much of the audience when the Foghorn Leghorn cartoons first premiered but like many of the references in WB cartoons of the era they have since become dated and "go over the heads" of most modern-day audiences.
A leghorn is a breed of chicken, and foghorn describes the character's piercing, monotonous voice.
All of the motion picture Foghorn Leghorn cartoons were directed by Robert McKimson.