The code name of the G.I. Joe team’s first medic, known for his trademark hat, is Doc.
Doc is the team’s original medical specialist in the A Real American Hero era. His real name is Carl Greer, and he is portrayed as a physician who also receives military training. The character first appeared in the 1982 Hasbro toy line and the Marvel Comics series, helping establish the team’s medical-support role alongside its combat specialists.
His distinctive hat is one of Doc’s most recognizable visual features, making him easier to identify among the original Joes. He is sometimes confused with Lifeline, who became another prominent G.I. Joe medic in later releases, but Lifeline is a separate character and not the team’s first medic.