Killbuck was a tribal leader of the turtle clan of the Delaware Indians. He became a leader when his grandfather, Newcomer, died in 1776.
During the early 1770s, missionaries, including David Zeisberger and John Heckewelder, arrived in the Ohio Country near the Delaware villages. The Moravian Church sent these men to convert the natives to Christianity. The missionaries established several missions, including Gnadenhutten, Lichtenau, and Schoenbrunn. The missionaries asked that the natives forsake all of their traditional customs and ways of life. Many Delawares did adopt Christianity, but others refused to do so. The Delawares became a divided people during the 1770s. This was even true for Killbuck's family. Killbuck resented his grandfather for allowing the Moravians to remain in the Ohio Country. The Moravians believed in pacifism, and Killbuck believed that every convert to the Moravians deprived the Delawares of a warrior to stop further white settlement of their land.
During the French and Indian War Killbuck actively assisted the English against their French enemy. In 1761, Killbuck led an English supply train from Fort Pitt to Fort Sandusky. The British paid him one dollar per day.
Killbuck became a leader in a very dangerous time for the Delawares. The American Revolution had just begun, and Killbuck found his people caught between the English in the West and the Americans in the East. At the war's beginning, Killbuck and many Delawares claimed to be neutral. In 1778, Killbuck did give permission a force of American soldiers to traverse Delaware territory so that the soldiers could attack Fort Detroit. In return, Killbuck requested that the Americans build a fort near the natives' major village of Coshocton to provide the Delaware Indians with protection from English attacks. The Americans agreed. While the Delawares had begun to side with the Americans, other groups, especially the Wyandot Indians, the Mingo Indians, the Munsee Indians, the Shawnee Indians, and even the wolf clan of the Delaware Indians favored the British. The English natives planned to attack Fort Laurens in early 1779 and demanded that the neutral Delawares formally side with the British. Killbuck warned the Americans of the planned attack. His actions helped save the fort, but the Americans still abandoned it in August 1779. The Delawares had lost their protectors and, in theory, faced attacks from the English, their native allies, and even American settlers that flooded into the area in the late 1770s and early 1780s. Most Delaware Indians formally joined the British after the American withdrawal from Fort Laurens.
Facing pressure from the British, the Americans, and even his fellow natives, Killbuck hoped a policy of neutrality would save his people from destruction. It did not.