After training as a nephrologist, he entered private practice and joined the military with the Puerto Rico National Guard and the U.S. Army Reserve in Fort Meade Maryland. He was sent to active duty during the Gulf War and assigned to Walter Reed Army Medical Center. In 1967, he became politically active, participating in the pro-statehood campaign leading to the July 27 political status plebiscite, as a leader of Estadistas Unidos (Statehooders United), a non-partisan group founded by long-time Statehood Republican Party gubernatorial candidate Luis A. Ferré. On August 20, 1967, at the assembly in Carolina, Puerto Rico at which the organization was dissolved, Padilla and other party leaders proposed the creation of a new political party that would eventually be known as the New Progressive Party (NPP) or Partido Nuevo Progresista (PNP) in Spanish.
