Wayne Mitchell is an agent with the U.S. Secret Service.
As the first recorded adventure of this highly efficient member of the historied division of first the Treasury Department and now Homeland Security takes place, Mitchell is barely into his 30s and has been with the organization for six years. Prior to his acceptance into the organization, he had been a member of the U.S. Marine Corps, rising to the rank of Captain.
This time frame would indicate that Mitchell, who was said to have been a well-respected officer in the Marines, must have been a tad better than that because the average age for making Captain is 27 and he would have had to make it at least two years earlier. Considering his prowess displayed as a T-Man, that is not unexpected.
He is described as "6' 3"" with "a sculptured physique of 210 pounds", an "imposing figure". He is further said to have "rugged handsome features" making him an attractive candidate as there was no "female in Washington who wouldn't want him guarding her". Despite this appeal to the ladies, Mitchell has always maintained his professionalism and has not strayed outside his approved lines of behavior.
One big quality that defines Mitchell is "loyalty". He is absolutely trustworthy in his determination to be true to his oath to protect his charges and nothing is allowed to interfere. Furthermore, his devotion to duty results in those he is protecting becoming steadfastly loyal to him. They trust him and have his back with the inevitable happens and things go wrong.