John Bishop Jr. was a resident of New London, born in 1834, who worked as a clerk. Like so many of his fellow citizens, he volunteered for military service in the weeks following the Confederate attack on Fort Sumter. He was mustered into Company E of the 2nd Connecticut Infantry as a sergeant on May 7, 1861 and after a very short period of training was sent to Virginia for what was expected to be a brief conflict. The regiment saw combat at the First Battle of Bull Run, but on August 7, soon after their three month term of service expired, they were discharged. Bishop volunteered again for the 1st Connecticut Heavy Artillery in April of 1862 at the outset of the Peninsula Campaign.

Connecticut was comparatively slow to organize African-American volunteers for the war effort and it was only in November of 1863 that the General Assembly and governor allowed the creation of an African-American regiment. Nevertheless, when the 29th Connecticut Colored Volunteer Infantry was formed, the state had no difficulty finding soldiers to fill its ranks. John Bishop requested a commission to serve as a lieutenant in the regiment and it was granted on December 22. Sgt. Mortimer Lee and Pvt. Edward Pease of Company E of the 1st Connecticut Artillery were also promoted to lieutenant in the 29th.

Although late to the front, the 29th saw action at the siege of Petersburg and was the first regiment to reach the abandoned Confederate capital of Richmond. After Lee's surrender, the 29th was shipped to Texas and was stationed in Brownsville through the summer and fall. In November of 1865, the men of the 29th were returned to Connecticut and discharged. According to his military history, Bishop participated in the battles around Petersburg and Richmond, but he also spent some of this period detached from his company, in service as assistant Provost Marshal and as aide-de-camp to Brevet Major General Giles Smith.