Moses Sheppard's earliest recollection of home was a dirt-floor cabin. He once said that he had given away or lost more than he ever expected to possess. His family, loyal to England, lost its property during the Revolutionary War. Moses Sheppard began working as an errand boy for a merchant, John Mitchell. Within a few years he became Mitchell's partner and then succeeded him as the firm's sole proprietor. Like many Quakers, he was active in the abolition movement and an active supporter of the Protective Society of Maryland to Protect Free Negroes; the American Antislavery Society; and the Society of Friends Indian Affairs Committee. Sheppard was influential in stopping legislation that would have banished free African-Americans from Maryland. He left the fortune he had amassed during his lifetime to found the Sheppard Asylum.

Sheppard and Pratt Hospital

Moses Sheppard spent years planning for a new hospital for the mentally ill, studying the designs of the best asylums in the country and the most advanced and humane methods of treatment. Three hundred acres of land on Charles Street and York Road in one of the most picturesque sections of Maryland were acquired for the new institution. Chartered in 1853, the cornerstone for the building was laid in the spring of 1862. The entire complex opened for patients in December of 1892. The Sheppard Asylum was considered the most advanced in the country for its time.

In 1898 a bequest from Enoch Pratt added a substantial endowment to the hospital. The name of the hospital was then changed to Sheppard and Enoch Pratt.