Peter Francisco entered the 10th Virginia Regiment in 1776 and served in the Continental Army's northern campaigns. His later petitions describe fighting at Brandywine and Germantown, a musket wound at Monmouth and participation in the assault on Stony Point. At Stony Point he received another serious wound and recovered at Fishkill. His size and strength attracted stories that grew through retelling.

After his Continental service Francisco volunteered again in the southern theater. He served in Virginia mounted units, including detachments associated with William Washington, and fought at Camden and Guilford Courthouse. His account of Guilford described a severe bayonet wound. Later narratives credited him with extraordinary feats against British cavalry and with carrying a cannon; those details should be treated as tradition rather than accepted at face value. His retrospective claims also require comparison with other records.

After the war Francisco married, managed property and sought financial recognition for his service. Petitions to Virginia in 1784, 1790 and 1821 asked for compensation, repeatedly emphasizing horses lost through wartime service. The legislature paid for one horse, while later claims introduced other expenses. These documents preserve both military recollections and the practical cost of volunteering. In his final years he worked as sergeant-at-arms for the Virginia Senate. He died at Richmond in January 1831 and received a public funeral.