During the 1850s, William Paul resided in Philadelphia's Spring Garden neighborhood (5th Ward) with his parents and sisters: Frances, Virginia, Mary, Emma, and Ida, who were born, respectively, circa 1834, 1836, 1838, 1847, and 1854.

[9] At the end of March, following basic training, he was transported with his regiment by rail to Baltimore, Maryland, quartered at the Patterson Park Barracks, and equipped with an altered smooth-bore musket before being moved again, by way of Washington, D.C., to Aquia Creek Landing, and assigned with his regiment to the 2nd Brigade, 2nd Division of the U.S. Army's 1st Corps under the command of General Irvin McDowell.

[10] Three days later, while fighting with his regiment in the Battle of Antietam on September 17, 1862, William Paul performed the act of valor which later resulted in his being awarded the U.S. Medal of Honor.

[11] In recalling those events for an interviewer years later, Paul said:[12] During the battle of Antietam, our corps was being vigorously attacked in a wooded and hilly part of the country, where our forces could not very well cope with an enemy accustomed to bush fighting.

Nevertheless, in a hard and deadly struggle we were slowly but surely driving the enemy back, when Color-Sergeant Mason, who was in advance of our lines some four or five yards, cheering us on, was shot.

Ordered to fatigue duty in the New Year, they then participated in the Mud March led by Major-General Ambrose Burnside (January 1863) and the intense fighting of the Chancellorsville Campaign (April 30–May 6) before heading for Pennsylvania.

The line was established behind a slight rise of ground, with small trees and bushes in front, the right of the Ninetieth being separated from the rest of the brigade by a road which it was impossible to occupy, being raked by the enemy’s artillery.

From some misunderstanding, or not having received the same peremptory order from General Griffin that he gave to the Ninetieth, the rest of the brigade did not advance any distance, leaving the regiment entirely alone in the charge.

When Colonel Lyle discovered that he was unsupported, he gave the order to ‘about face,’ and what was left rallied around the colors, and under a fierce fire of infantry and artillery returned to its original position….

A ditch run across the field with rebel sharp-shooters, who prevented any of the wounded from being taken off, and they fell into the hands of the enemy.’ The regiment was soon after relieved and moved to the rear.Reassigned to the 3rd Division of the 5th Corps, the division under General Samuel W. Crawford, Paul's regiment became one of those which fought in the Battle of Cold Harbor (June 1–12) and several other engagements during the Siege of Petersburg (June 9, 1864 – March 25, 1865).

[19][20][21] Following his honorable discharge from the military, William Paul returned north, and resumed life at home with his parents and younger sister, Ida.

[30] Once again a resident of Bel Air during the early 1900s, he supported his wife, Annie, and daughters, Mary and Barbara, through business employment as an agent.

According to several reports by The Aegis & Intelligencer newspaper:[32] ”August 15, 1902.... Mr. William H. Paul, of Earlton, who was wounded three times in the battle of the Wilderness in 1864, expects to go to Philadelphia to undergo an operation, which will be performed by his former surgeon Dr. Meers.

[33] By 1910, his daughters had moved out of the family home to begin their own lives, leaving Paul and his wife to reside in Harford County as empty nesters.