His father, Benjamin Hallowell III, Esq., was the Commissioner of Customs, and the family lived in the Jamaica Plain end of what was then the town of Roxbury, just south of Boston.

He continued to donate large sums of money to Harvard, and in 1810 gave them a valuable collection of medical and anatomical works and engravings.

[4] The Suffolk County Records state that "To the inhabitants of the town of Princeton he gave $1000, one half to be paid to the deacons of the Church and congregation over which Rev'd Samuel Clarke was pastor, the net income to be applied towards the salary of the minister.

The remaining five hundred dollars to be loaned to industrious young men in the town until it doubled when the income should be expended for the support of indigent and deserving widows and female orphan children.

While residing in London he became familiarly acquainted with the celebrated Dr. John Hunter, and having had two uncles in this country distinguished members of the medical profession, he became greatly interested in all matters pertaining to medicine.