Hosmer was born at Middletown, Connecticut, in 1737, the third son and eighth child of Capt. Stephen and Deliverance (Graves) Hosmer. He was descended from Thomas Hosmer of Hawkhurst, Kent, England, who settled at Newtown (Cambridge, Massachussets) before 1632 and went with Thomas Hooker to Hartford in 1636.
After receiving his preliminary education, Hosmer entered Yale College and was granted the degree of A. B. in 1757, receiving a Berkeley scholarship at graduation. He then studied law.
Upon his admission to the bar settled in Middletown to practise his profession. A lawyer of ability, Hosmer speedily won for himself a successful practice as well as sundry civil offices. After holding several town offices and serving as justice of the peace, he was elected in October 1773 a representative to the General Assembly. He was repeatedly reëlected until May 1778 when he was elected an Assistant, and this office he held by annual reelection up to the time of his death.
As speaker of the House of Representatives in 1777, he did much to influence the legislature to prosecute vigorous measures against Great Britain. During part of the Revolutionary War he was a member of the Committee of Safety, and in 1778 was a member of the Continental Congress and one of the signers of the Articles of Confederation (July 9, 1778).
Hosmer had a natural taste for good literature and collected a library of more than two hundred books. His home was a rendezvous for people of culture for he was a courteous and genial host and found great pleasure in intelligent company. Joel Barlow credits the writing of his chief poetical attempt, The Vision of Columbus, to the interest and encouragement given him by Hosmer.
In deliberative bodies, Hosmer commanded attention and admiration by his clear and logical argumentation. Noah Webster ranked him with William Samuel Johnson of Stratford, and Oliver Ellsworth of Windsor, chief justice of the United States. By an act of Congress of January 15, 1780, a court of appeals consisting of three judges was formed, its principal function being the revision of maritime and admiralty cases. To this court Hosmer was elected a member, but he never entered upon the duties of the office for he died suddenly within a few months after his appointment.
In November 1761, he was married to Lydia Lord. They had seven children, the eldest of whom was Stephen Titus Hosmer, later chief justice of the supreme court of Connecticut.
