Increase was born on November 27, 1746 in Roxbury, Massachussets, United States. He was the son of Increase Sumner, a well-to-do farmer of colossal size and strength, and Sarah (Sharp) Sumner, daughter of Robert Sharp of Brookline and first cousin of John Adams' mother. He was descended from William Sumner who came to Massachusetts about 1635 and settled in Dorchester.
Having prepared for college in the Roxbury grammar school (now Roxbury Latin school), he entered Harvard, where he was graduated with distinction in 1767. He then taught in the Roxbury school for two years, studying law meanwhile under Samuel Quincy, solicitor general of the province and loyalist brother of Josiah Quincy the patriot.
After admission to the bar in 1770, Sumner opened an office in his Roxbury home. His practice soon became important and lucrative. Early in life he took from the arms of the Kentish Sumners the motto, In medio tutissimus ibis, and shaped his whole political career accordingly. Though he was mildly opposed to the British contentions, his only part in the Revolution was to serve as representative in the General Court, 1776-79; and as senator, 1780-82.
He was a member of the constitutional convention whose work was rejected by the voters in 1778, and of the convention of 1779-80 that framed the Massachusetts constitution. In June 1782 the legislature elected him to Congress to fill a vacancy, but he never sat because in August he was appointed associate justice of the supreme judicial court of Massachusetts.
The work of the judges needed much courage during the turbulent times when the new state government had just been set up and there was much hostility to the common law and those who enforced it. The judges, as Sumner's portrait shows, still wore their pre-Revolutionary black silk gowns with white bands, but despite Sumner's vigorous protest Chief Justice Dana, followed by the other justices, soon abandoned them, and they were not resumed until 1901.
Since the judges did not habitually write out their decisions until 1804, no printed reports of his legal views exist, but the Massachusetts Historical Society possesses his manuscript notes of his cases. As a member of the Massachusetts convention of 1788 which ratified the federal Constitution, Sumner delivered several speeches, especially in support of biennial rather than annual elections of Congress.
In 1797, Adams having retired, Sumner swept the state against the divided Democratic-Republican opposition of James Sullivan and Moses Gill, and was sworn in as governor on June 2, 1797, his tall and commanding figure a striking contrast to the gouty infirmity of Hancock, who had to be carried to the Council chamber in a chair, and to the bent old frame of Adams.
Having inherited considerable property from his father-in-law, he entertained lavishly and drove a coach and four on all public occasions. His middle-of-the-road policy was just what Massachusetts needed to calm the dissensions aroused by the proposed French war and the Alien and Sedition Acts.
He was reelected in 1798 and 1799 by overwhelming majorities, getting the unanimous vote of many towns. At his third election in 1799 he was ill with angina, and he was sworn in on his death bed in Roxbury.
Increase Sumner was the fifth governor of Massachusetts, serving from 1797 to 1799. He was elected on that post three times by wide margins. During his administration, the government was removed to the new State House on Beacon Hill. His chief activities were in military affairs. He worked to increase munitions, obtain additional arsenals for the artillery, and fortify the sea coast of the state.
Almost against his will, Sumner was put forward by the Federalists in 1796 as their gubernatorial candidate against Samuel Adams. There was little to recommend him in comparison with Adams, who was triumphantly reelected.
He was solid and judicious rather than brilliant. His personality was impressive but kind.
Quotes from others about the person
According to W. H. Sumner, Sumner acquired a reputation as "a dispassionate, impartial, discerning, able and accomplished judge. He never forgot his dignity in any place or circle, even in the moments of his greatest familiarity"
According to Morse, "He had indeed 'united all hearts, ' and his freedom from political bias made of him a refreshing and admirable contrast to the bitter actions and animosities of the politicians of that period".
According to Knapp, "In the analysis of his mind there is not to be found one extraordinary power, nor one mean quality".
He married, September 30, 1779, Elizabeth, daughter of William Hyslop, a prosperous Boston merchant. She survived Sumner, leaving a son and two daughters.
His descendants include his son William H. Sumner, for whom the Sumner Tunnel in Boston, Massachusetts is named, and 20th-century diplomats Sumner Welles and Sumner Gerard.
