As a slave trader in his sailing days, he owned at least one African as well. In fact, Whipple’s slave, Prince, would fight alongside him the coming war, one of perhaps five thousand black soldiers who fought for the American cause. A year before independence Whipple retired from business and devoted the rest of his years to public service.

He was appointed commander of the first regiment of New Hampshire Militia in the first state to declare independence from Great Britain. His service in the Committee of Safety led to his appointment as a delegate to the Continental Congress, where he joined the other two New Hampshire men in signing the Declaration of Independence. As one historian of the convention wrote in 1824:

The memorable day which gave birth to the Declaration of Independence afforded, in the case of William Whipple, . . . a striking example of the uncertainty of human affairs, and the triumphs of perseverance. The cabin boy, who thirty years before had looked forward to a command of a vessel as the consummation of all his hopes and wishes, now stood amidst the Congress of 1776, and looked around upon a conclave of patriots, such as the world had never witnessed. He whose ambition once centered in inscribing his name as commander upon a crew list, now affixed his signature to a document, which has embalmed it for posterity.

The following year, he was appointed brigadier general by the assembly of New Hampshire, one of sixteen signers who would see military service in the course of the war. Whipple’s heart ailment, which caused occasional fainting, did not affect his strong heart for defense of his state. After the loss of Fort Ticonderoga to the British and their three-pronged invasion of New York, the New Hampshire troops led by John Stark (“we will gain the victory or Molly Stark’s a widow”), and William Whipple met a force of Germans and Indians at Bennington, New York and destroyed or scattered their entire army. At the decisive Battle of Saratoga, the New Hampshire men played a key role in defeating and capturing General Burgoyne’s army.

In the course of the conflict General Whipple presented Captain John Paul Jones with orders to command The Ranger out of Portsmouth and fought in Massachusetts and Rhode Island, where a cannonball narrowly missed him but struck a major as it passed through his headquarters. Probably due to ill-health, General Whipple retired from the army in 1778 though he continued to serve in the New Hampshire assembly and receive appointments by the American Congress, which he turned down with regret. From 1782 till his death of a heart attack in 1785, age 55, Whipple served as associate justice of the superior court of New Hampshire. He freed his servant, Prince, a year before his own death and they are both buried in the same cemetery and marked with Revolutionary War veteran on their tombstones.

The encomium of a later historian provides a fitting epitaph of the third signer of the Declaration of Independence:

“General Whipple was possessed of a strong mind, and quick discernment: he was easy in his manners, courteous in his deportment, correct in his habits, and constant in his friendships. He enjoyed throughout his life a great share of the public confidence, and although his early education was limited, his natural good sense, and accurate observations, enabled him to discharge the duties of the several offices with which he was entrusted, with credit to himself and benefit to the public. . .[his] memory will be long cherished in New Hampshire, and whose name, united with the great charter of our freedom, will perish only with the records of the Republic.”