- "Rogers! I said, 'Fall in'!"
- ―Michael Duffy to Steve Rogers
Sergeant Michael Joseph Duffy was Steve Rogers' drill sergeant while in basic training.
After 17 years of training new recruits at Camp Lehigh, in 1943, Sergeant Michael Duffy was assigned by Colonel Chester Phillips to instruct the candidates of Project Rebirth, Gilmore Hodge and Steve Rogers among them. One of the exercises that he gave was for the candidates to retrieve a flag on a wet, slippery flagpole, where the prize would be to ride back to camp with Peggy Carter after a grueling run. As the candidates swarmed the pole, Duffy cheered for Hodge to reach the goal, as Rogers watched and regained his composure. When the others failed and tired, Rogers disconnected the pin holding the pole, retrieved the flag and handed it to Duffy as he got into Carter's jeep.
Sometime later, while Duffy continued to train the candidates, Chester Phillips threw a fake grenade among them. After Rogers made a possible self-sacrificing move by covering the grenade, Duffy ordered him to get up when it was learned that it was a dud.
- Comic books were created depicting fictional adventures of Captain America and a fictional version of Sergeant Duffy was created as well.