Peter Madison was a commissioned officer in the United Federation Marine Corps.
Originally a warp fighter pilot, he switched to Marine Special Operations Command after ejecting from his fighter over a barren word in the Demilitarized Zone in 2370. He was stranded for almost eight months. ("Bailout")
He served as the 101st Tactical Wing's Strategic Operations Officer after Operation Return until the end of the Dominion War.
Madison worked closely with Lieutenant Commander Seff O'Rourke on several operations during the war.
In the last days of the Dominion War, he was promoted to Lieutenant Colonel and formed an elite unit of Starfleet and Marine personnel. The unit's first mission was to extract a highly placed operative from Kora II. ("Snatch")