He married Blanche Marie Pate, who was said to have been his teacher.  They were married Nov. 1, 1905.  Their third, and last, child was John William Cox, Jr . The wedding announcement is given below as it appeared in The Sumter Daily Item (dated November 2, 1905, pg. 3 column 3):

"The mystics of "All Hallo'een" had just subsided into twilight under the canopy of the Harvest Moon, when the culmination of a surprise romance was solmenized into marriage last evening at the residence of the bride's brother, Mr. J. Frank Pate, who the young couple had confided their secret best known to two.  Mr. J. William Cox, of Moultrie, Ga. and Miss Marie Blanche Pate were united into marriage by the Rev. Pierce Kilgo, of the First Methodist church.  The bride was handsomely gowned in a dark green broadcloth tailor-made suit.  Miss Blanche is one of Sumter's most brilliant and accomplished young ladies.  Not in society's gay hall's has she sought to shine but quite unostentatiously she has gone like the good Samaritan into homes of loneliness, her bright disposition left rays of sunshine.  It is with much reluctance Sumter gives to Georgia this young daughter of lovely personality who numbers her friends by her smiles.

   Mr Cox is the grandson of the late Dr. Kennedy of Ridgeway, of eminent fame.  He is a young man of fine character and business qualities and is meeting with much success in his mercantile work.  He is to be congratulated on winning so charming a wife.

   Mr. and Mrs Cox left immediately on their bridal tour hence to their home in Georgia."

Apparently, they didn't live in Georgia for long, since Walsh's directory for Sumter, SC (1905-06) shows them living at 111 Kendrick with John's sister Alma Irene Cox and his grandmother Emma L. (Watts) Kennedy.  The Census of 1910 lists them back at the home of Blanche (201 E. Liberty St. in Sumter, SC) that they shared with her two unmarried older sisters (Luticia and Mattie Pate ). John worked for most of his life at the O.L. Williams Veneer Company as a shop foreman in the coat hanger department.  He was a Masonic Lodge member.  Based on items that survive from his life, he apparently was very interested in photography, radio and cabinet making.

The marriage announcement comments about "Mr Cox is the grandson of the late Dr. Kennedy of Ridgeway, of eminent fame" are puzzling.  His maternal grandfather was Arthur Burgess Kennedy.

The marriage was also published in the Nov.8, 1905 Watchman and Southron.  Also see link to LOC page. This announcement is 1 week later than the one noted above.

It is not known who wrote the marriage announcement; reference to John's grandfather Arthur Burgess Kennedy as "Dr." Kennedy is puzzling, since census records indicate that he was a farmer. The census of 1900 shows John and his sister Alma living with their maternal grandmother, Emma L. (Watts) Kennedy . Walsh's phone directory (1905-06) shows him living with his sister Alma at 111 Kendrick.  He is employed at the Sumter Telephone Manufacturing Co.  Note that the census of 1930 indicates that he was "a veteran of the U.S. military or naval forces mobilized for any war or expedition", with "WW" indicated as the war or expedition; see his World War I registration card.

He is buried at Sumter Cemetery (Sumter, SC).