Osceola was named Billy Powell at birth in 1804 in the village of Tallassee, Alabama around current Macon County. His mother Polly Coppinger was daughter of Ann McQueen, who was part Muscogee and part Scottish. Many sources, including the Seminole, state that Osceola's father was an English trader William Powell.
In 1832, a few Seminole chiefs signed the Treaty of Payne's Landing, by which they agreed to give up their Florida lands in exchange for lands west of the Mississippi River. Five of the most important of the Seminole chiefs, including Micanopy of the Alachua Seminoles, did not agree to the move. In retaliation, Native American agent Wiley Thompson declared that those chiefs were removed from their positions. As relations with the Seminoles deteriorated, Thompson forbade the sale of guns and ammunition to the Seminoles. Osceola, a young warrior beginning to rise to prominence, was particularly upset by the ban, as he felt it equated Seminoles with slaves.
In spite of this, Thompson considered Osceola to be a friend, and gave him a rifle. Later, though, when Osceola quarreled with Thompson, Thompson had him locked up at Fort King for a night. The next day, to get released, Osceola agreed to abide by the Treaty of Payne's Landing and to bring his followers in. On December 28, 1835 Osceola and his followers ambushed and killed Wiley Thompson and six others outside of Fort King.
On October 21, 1837, on the orders of U.S. General Thomas Sidney Jesup, Osceola was captured when he arrived for supposed truce negotiations in Fort Payton. He was imprisoned at Fort Marion, St. Augustine, Florida. Osceola's capture by deceit caused a national uproar. General Jesup and the administration were condemned. That December, Osceola and other Seminole prisoners were moved to Fort Moultrie, South Carolina. They were visited by townspeople.
George Catlin and other prominent painters met him and persuaded him to pose. Robert J. Curtis painted an oil portrait of Osceola as well. These pictures inspired a number of other prints, engravings, and even cigar store figures. Afterward numerous landmarks, including Osceola Counties in Florida, Iowa, and Michigan, were named after him, along with Florida's Osceola National Forest.