Son of Capt. Nathaniel and Almira (Pierce) Johnson.
On 3 May 1857 Joseph Pierce Johnson, 22, married Keziah Wood, 18, daughter of Myles and Melinda (Montjoy) Wood, at Northborough, Massachusetts.
On 12 Jul 1861 Joseph, a comb maker, mustered into service with the 15th Massachusetts Volunteer Infantry, being credited to the quota of Northborough, Worcester County, Massachusetts.
He was 26 years, 10 months and 17 days old.
Joseph and James Nathaniel Johnson, brothers, served together in Co. C of the 15th Massachusetts Volunteer Infantry.
At the battle of Antietam, as orderly sergeant, he became the commanding officer of his company, on account of the deaths or disabilities of his superior officers.
He made a gallant stand with his men. In his eagerness to hold their position, he kept reiterating the order: "Close up, boys; don't let them push us back," and in his delirium died with these words on his lips.
He was wounded September 17, 1862, and died October 4, 1862, at Mt. Pleasant Hospital, Washington. His embalmed body was brought home by the town and buried with the highest military and civic honors in Howard Street cemetery, Northborough.