Johnny Dale is an agent with the Secret Service.
He carries a badge, wears a regulation suit all the time, flashes his badge routinely to identify himself as an agent, and yet is referred to as a "secret agent". Secrecy is not that terribly prevalent in Dale's activities but being an agent definitely is. Perhaps the epithet is applied because, as the opening of his first recorded adventure says, "The Secret Agent works alone! And at the end of the job...there is no glory waiting for him...no newspaper headlines...no medals...But he knows that he has served his country at the risk of his life! And, after all, what greater reward can a man earn?"
By his depictions as well as his confidence and abilities, we can safely deduce that Dale has been an agent for a fair number of years with this age being roughly in his early to mid 30s. He has a good way with the opposite sex but is not so blasé about himself that he cannot blush when given a kiss on the cheek by a beautiful princess.
Dale is a darn good shot and takes out a fair number of bad guys, which is a good thing for him because in almost every mission we follow him on, someone is there to whallop him over the head with something. The agent's head has to be made of steel. He is also resourceful and not a little daring as shown by his swinging from a cargo ship net onto a pier to slug it out with guys with guns.
We are shown at the end of the first adventure that he loves the excitement and challenge of a good case when having completed one harrowing mission, he eschews a rest saying "That was just a warm-up. I'm looking for some real action now!"