WILLIAM COX was born in Pennsylvania in August of 1842. His father was Jacob Cox, a shoemaker. William Cox's mother Mary appears to have died while William was quite young, father and son were living in South Camden by 1850, and Jacob remained unmarried through 1860. When the Census was taken in 1860, William Cox was still living with his father, and had begun working as an apprentice bricklayer. Older brother John had come to live with them as well.

 In April of 1861, the Civil War began. William Cox answered his nation's call to arms. On April 25, 1861 William Cox enlisted in the Union Army as a Private. He was assigned to Company G, Fourth Infantry Regiment New Jersey on April 27, 1861. 

The Fourth Regiment--Militia, was commanded by Colonel Matthew Miller, Jr., serving under him were Lieutenant Colonel Simpson R. Stroud and Major Robert C. Johnson. This regiment was mustered into the U. S. service at Trenton, April 27, 1861, to serve for three months, and left the state for Washington, D. C., on May 3, with 37 commissioned officers and 743 non-commissioned officers and privates, a total of 777. On the evening of May 5 it reached the capital, and on the 9th it was ordered to go into camp at Meridian hill, where, within a few days the entire brigade was encamped, and where, on the 12th, it was honored by a visit from the president, who warmly complimented the appearance of the troops. On the evening of May 23 it joined the 2nd and 3d regiments and about midnight took up the line of march in silence for the bridge that spanned the Potomac. This bridge was crossed at 2 o'clock on the morning of the 24th, the 2nd was posted at Roach's spring, and the 3d and 4th about half a mile beyond on the Alexandria road. On July 16, a guard was detailed from the 4th for a section of the Orange & Alexandria railroad, which it was important to hold; one company from the regiment guarded the Long bridge; still another was on duty at Arlington mills; and the remainder of the regiment, together with the 2nd, was ordered to proceed to Alexandria. On July 24, the term of service having expired, the 4th returned to New Jersey and was mustered out at Trenton, July 31, 1861. The total strength of the regiment was 783, and it lost by discharge 6, by promotion 2, by death 2 and by desertion 7, mustered out, 766.

William Cox was among those who mustered out with Company G, Fourth Infantry Regiment New Jersey on July 31, 1861 at Trenton, NJ. 

Several men who served with Company G became members of the Camden Fire Department after it was founded in 1869, including William W. Mines, J. Kelly Brown, Henry F. Surault, Edward Mead, Benjamin Cavanaugh, James M. Lane, and William Gleason. Other Fourth Infantry men who served included Theodore A. Zimmerman, Charles G. Zimmerman, William C. Lee, George B. Anderson, Jesse Chew, William H.H. Clark, Cornelius M. Brown, John J. Brown, Benjamin Connelly, and G. Rudolph Tenner. Several other Fourth Infantry veterans played significant roles in Camden in the ensuing years.

The 1870 census shows William Cox living with his father and brother in South Camden. William Cox was working as a painter at the time of the Census. In the summer of 1871, William Cox was appointed to the Camden Fire Department to take the place of J. Kelly Brown as an extra man with Engine Company 1. Brown had been transferred to Engine Company 2 on July 18, 1871.

William Cox was working as an engineer, when appointed to the Fire Department. He was then making his home at 306 Pine Street. He later returned to working as a painter.

On March 8, 1872 William Cox was removed from service with the Camden Fire Department.

The 1878 City Directory shows William Cox, tobacconist, at the southeast corner of North 4th and Arch Streets, and the 1880 census shows William Cox, wife Mary, and daughter Sarah living at 402 Arch Street. His occupations are given as tobacconist and painter. William Cox maintained a tobacco shop at this corner into the early 1900s. Around 1889 or early 1890 he moved to 400 Arch Street.

By 1900 William Cox was a widower. He was then living at 400 Arch Street with Harriet Francisco, whose occupation is listed as "housekeeper". William Cox is not listed in the 1906 Camden City Directory.

The 1910 Census shows William Cox living at 616 Vine Street, with his nephew William H. Cox and family. Brother John, who was William H. Cox's father, also lived at that address. William Cox was no longer working according to the census. William Cox is listed in the 1910-1911 Camden City Directory. William Cox died on June 5, 1912 and was buried at Evergreen Cemetery. Cemetery records state that he was 67 years old at the time of his passing.