A Virginian by birth, John Love embarked upon a career in the military with an appointment to the U.S. Military Academy from Tennessee. After graduating fourteenth in the class of 1841, a class that produced twenty Civil War generals, John Love was commissioned as 2nd Lieutenant of the 1st Dragoons and sent to Fort Leavenworth, Kansas, under the command of Capt. Philip St. George Cooke. Over the next several years, the Dragoons operated widely over the west, serving to protect emigrants and interlopers onto Indian lands, and providing military muscle against Indian resistance.
Love rose slowly, but steadily through the ranks. During the Mexican War, the 1st Dragoons played a significant role in several engagements in Alta California and Mexico, and for his actions, Love was promoted to 1st Lieutenant (June 1846) and a received brevet Captaincy for gallant and meritorious service at the Battle of Santa Cruz de Rosales (March 1848). Upon his return to the States, he initiated a courtship with Mary F. Smith of Indianapolis, a belle, as some of her friends suggested, with tendencies to coquettery, who was simultaneously entertaining the attentions of at least two other men. In the early fall of 1849, the couple married and shortly thereafter, moved to Fort Leavenworth where Love assumed duties as quartermaster for the 1st Dragoons (1849-50). Subsequently, he was posted in the more civilized environs of Jefferson Barracks, Mo. (1849-51) and was assigned to recruiting duty (1851-52) before finally resigning his commission in February, 1853, to settle down to life as a railroad contractor in Indianapolis. The couple appear to have a had at least one child, a daughter born within a year of their marriage.
Love returned to military service during the Civil War. As an experienced military man and captain in the Indiana militia (1858-1861), Love was well prepared for his service in the West Virginia campaign during the summer of 1861. Late in 1861, he was commissioned Major General of the Indiana Legion, and filled various assignments, including training troops, coordinating the defenses at Cincinnati, and repulsing Morgan's raiders at Mount Vernon, Ind., in July, 1863. He officially resigned in January, 1863, and once again retired to Indianapolis, where he worked as a real estate broker and European agent for the Gatling Rifle Gun.