Jamie is a good-natured mailman that is first seen delivering Steven's Cheeseburger Backpack. His uniform consists of a light blue button up shirt with an envelope embroidered on both sleeves, a white shirt beneath it, cobalt blue shorts, a messenger satchel with an envelope embroidered on its flap, and a pith helmet. He also wears a pair of white socks under a pair of red shoes with white lining. He has a prominent nose, thick eyebrows, thick brown hair, and soft-black eyes.
In the episode "Historical Friction", Jamie changes into a casual outfit consisting of a black v-neck shirt and brown-green pants. His costume for his role in the play is a red turtleneck and a small white sailor hat.
Jamie is easygoing, friendly, kind, and is (mostly) dedicated to his job. While he takes his duties seriously, his real dream is to be an actor. He considers himself a thespian, likes Shakespearean poetry, and has a flare for the dramatic (so much so that he and others refer to his bouts of overacting as being in "the drama zone"). He is very sensitive at times and does not take rejection well. His failed attempts to make it big in Kansas were particularly difficult for him to deal with.