He was born on February 8, 1805 in Londonderry, New Hampshire, United States, the son of Moses Cross and Lois (Cleaveland) Pilsbury. He was a descendant of William Pilsbury, or Pillsbury, who came to Boston late in 1640 or early in 1641, and married Dorothy Crosbey after an unconventional courtship.
Amos spent his early years on the home farm, but when his father became warden of the New Hampshire state prison in 1818 and the family moved to Concord.
He was sent to the academy in Concord. He was known as a "dull scholar" and his father soon apprenticed him to a tanner and currier.
When at the end of his apprenticeship he was unsuccessful in his attempt to find a journeyman's place at a living wage, he returned home and was in 1824 appointed guard in his father's prison and a year later, deputy warden. His father had already achieved a more than local reputation, having made his prison a financial asset to the state instead of a liability. For this reason, perhaps, he was called to the wardenship of the new Connecticut prison at Wethersfield in 1826, where Amos soon joined him.
When his father retired in 1830, because of ill health, Amos succeeded him, his youth causing the board of directors to express some misgivings about his election. Dissension between him and the directors soon ripened into warfare. In 1832 he demanded a legislative investigation of his work, was removed from office by a new board of directors, exonerated by the investigating committee, and reinstated in 1833, the Assembly compensating him both for the loss of his time and the cost of his defense.
He remained in office until 1845 when political fortunes caused his removal. He was immediately called to Albany, New York, to supervise the construction of the new county penitentiary, of which he later served as warden, except for a brief period, until his last illness prompted his resignation. Urged to accept the superintendency of the New York City institutions on Ward's Island, he was absent from his position from 1855 to 1860, the last eight months of this period being spent as general superintendent of the metropolitan police, from which position he resigned in protest against the efforts of Mayor Fernando Wood to secure political control of the department.
He died in 1873 in Albany, New York.
Amos Pilsbury and his father are said to have been the first professional prison wardens in the United States, Amos' service in three states covering a period of fifty years. His interest in jail reform made him propose to the General Assembly that each county be given a thousand dollars from the prison's surplus earnings on condition that its jail be rebuilt on the plan of the model jail at Hartford, and he was authorized to make such payments. He shared in the work of launching the National Prison Association of the United States (1870), now the American Prison Association, and he represented the State of New York at the International Penitentiary Congress in London in 1872.
He urged that the surplus be used to erect and maintain a special asylum for the criminal and pauper insane.
In spite of the early accusations which challenged his competency, all commentators upon his life work unite in approval of his humane attitude toward his prisoners, albeit he was a strict disciplinarian.
In 1826 he married Emily (Heath) Pilsbury, she borne him five children, three of whom died in infancy.
