Answer by taking a quote from the following article:

Juan Ponce de Leon (Spanish pronunciation: ['xwan 'ponthe de le'on]; 1474 - July 1521) was a Spanish explorer and conquistador born in Santervas de Campos, Valladolid, Spain in 1474. Though little is known about his family, he was of noble birth and served in the Spanish military from a young age. He first came to the Americas as a "gentlemen volunteer" with Christopher Columbus's second expedition in 1493. By the early 1500s, Ponce de Leon was a top military official in the colonial government of Hispaniola, where he helped crush a rebellion of the native Taino people.

In 1502 the newly appointed governor, Nicolas de Ovando, arrived in Hispaniola. The Spanish Crown expected Ovando to bring order to a colony in disarray. Ovando interpreted this as authorizing subjugation of the native Tainos. Thus, Ovando authorized the Jaragua Massacre in November 1503. In 1504, when Tainos overran a small Spanish garrison in Higuey on the island's eastern side, Ovando assigned Ponce de Leon to crush the rebellion. Ponce de Leon was actively involved in the Higuey massacre, about which friar Bartolome de las Casas attempted to notify Spanish authorities. Ovando rewarded his victorious commander by appointing him frontier governor of the newly conquered province, then named Higuey also. Ponce de Leon received a substantial land grant which authorized sufficient Indian slave labor to farm his new estate.  Ponce de Leon prospered in this new role. He found a ready market for his farm produce and livestock at nearby Boca de Yuma where Spanish ships stocked supplies before the long voyage back to Spain. In 1505 Ovando authorized Ponce de Leon to establish a new town in Higuey, which he named Salvaleon. In 1508 King Ferdinand (Queen Isabella having opposed the exploitation of natives but dying in 1504) authorized Ponce de Leon to conquer the remaining Tainos and exploit them in gold mining.  Around this time, Ponce de Leon married Leonora, an innkeeper's daughter. They had three daughters (Juana, Isabel and Maria) and one son (Luis). The large stone house Ponce de Leon ordered built for his growing family still stands today near the city of Salvaleon de Higuey.

What did he do in Hispaniola?
The Spanish Crown expected Ovando to bring order to a colony in disarray.