But little can be learned of the early life of this brave and noble officer. He came from Ireland to America in his boyhood. His grandfather fell at the head of a troop of horse fighting for the liberty of Ireland in 1798, and his grandson was thoroughly in earnest in 1861. He was a man of a strong, earnest nature, and a laborious student. He came to Monroe in 1854, as assistant civil engineer on the road. He then studied law. Joseph A. Sleeper, Esq., then one of the leaders of the bar in southern Wisconsin, said:
"My attention was called to the strength of his mind, evinced in the clearness of his replies, when we was examined for admission to the bar, and in his thorough understanding of the whole subject."
He was young without influential friends, but he was rising to a lucrative practice when the war broke out. When the first war meeting was held in April, 1861, at Monroe, Moses O'Brien was the first one to enlist. He was then district attorney for Green County. He was the first one to place his name on the roll. He did so, saying, "I learned to love liberty in the land of my birth; I came to America to enjoy it; I can fight to defent it. Give me the pen."
In the service he was the soul of loyalty to the cause and to his duty. His was one of the earliest promotions from lieutenant to captain in the regiment; and he was in camp and on the march remarkable for his care for his men. He was large of stature, strong, capable of great endurance, and always bearing the burden of some tired or sickly soldier. Kind-hearted, gentle as a child in camp, he had the rage of a hero in battle. He knew no fear, though he expected to fall in action. The circumstances of his death from wounds at Cedar Mountain, August 9th, 1862, are elswhere told. His body was taken to Milwaukee, where some of his relatives lived. There his funeral sermon was preached by Bishop Henni. A company of the Twenty-fourth and one from the Twenty-sixth regiments attended the funeral and acted as escort; and a long cortege of soldiers, friends and citizens followed the mains of this gallant hero to the grave. He was a loveable character, gentle, kind, modest, but earnest and brave. The men of Company C in which he first served, and Company I, in which he was captain when he fell, mourned him as a father, and the officers of the regiment loved him as a brother.
The bar of Green County passed appropriate resolutions and spoke with feeling eloquence. Their words were not those of mere eulogy when they said,
"that as a soldier, true patriotism was his strongest impulse. Ardent in the support of the glory of his adopted country, he fell nobly leading his forces in battle in that part of the fight where the death-storm raged the fiercest, and bravely met a death of glory; by the sacrifice earning the lasting gratitude of our people."