Obadiah Crosby was the sixth of seven sons of Obadiah Crosby, a native of Putnam County, New York. Obadiah was born in New Berlin, Chenango county, on the 5th day of May, 1800. For a time he was engaged as a teacher of a common school, and in 1828, taught the academy at Ballston Springs, having meantime given his attention to the study of medicine with Dr. St. John of that place. He attended medical lectures in New York, in the winter of 1828. After coming to Albany to reside he became a partner of Dr. Henry Greene, and united with the Society in 1830.
Dr. Crosby was appointed Brigade Surgeon on the staff of General Stephen Van Rensselaer. He was a gentleman of attractive personal appearance, indeed regarded as handsome, and in military equipage when mounted, made a brilliant and able officer. On returning from a military review in September, 1835, he was by some unfortunate circumstance thrown from his horse and received an injury which, though it appeared not serious at first, in its results began to disturb his health. He was so much of an invalid that in the autumn of 1837, his friends urged upon him the importance of seeking the influence of a warmer climate, and he accordingly went by way of Cincinnati, to New Orleans, but without deriving the desired benefit. He returned the following spring and lingered until the 1st day of July, 1838, when he died in the prime of manhood at the age of thirty-eight years.
Dr. Crosby was upright and honorable in all the relations of life, and many friends cherished him with an affectionate regard. He was a member of the Presbyterian church, and lived within its pale a life of exemplary piety.
Dr. Crosby left a wife and one daughter. His brother Alonzo Crosby is well known among the masonic fraternity of Albany, as tyler of the lodges.