Owen O’Brien was born around 1826 in Ireland. He eventually immigrated to America, and he may have lived in Maryland. By 1868, he was living in New Haven, Connecticut. He worked as a clerk in the adjutant general’s office.
In March 1869, adjutant general Colin Ingersoll reported that the “greater part of the work in the [pension] claim department during the past year has devolved upon Owen O’Brien, Esq., in charge of claims.” Ingersoll testified to O’Brien’s “integrity, industry and business talent.” The following year, the state legislature debated a resolution to pay O’Brien an extra $500 for “services at the hand of the bureau of pensions.” One legislator, however, denounced the resolution as an “insult to the general assembly and to the State.” He argued that O’Brien was “a scoundrel and a coward, and ought to be kicked out of the house.” The resolution was “indefinitely postponed.” He died sometime after March 1871.