Feliciano was born in Lares, Puerto Rico, one of eleven children. His blindness is the result of congenital glaucoma. He was first exposed to music at age three. When he was five, his family moved to Spanish Harlem, New York City and, at age nine, he played on the Teatro Puerto Rico.
He started out playing accordion until his grandfather gave him a guitar. He reportedly sat by himself in his room for up to 14 hours a day to listen to 1950s rock albums, classical guitarists such as Andrés Segovia, and jazz players such as Wes Montgomery. He later had classical lessons with Harold Morris who earlier had been a student with Segovia.
At 17, he quit school to play in clubs, having his first professional performance in Detroit. Feliciano became a household name all over Latin America. After moving to Los Angeles, he teamed up with Rick Jarrard who was, at the time, also producing Nilsson and Jefferson Airplane.
They recorded The Doors' song "Light My Fire" in a Latin style and released it as a single. It reached #3 on the US pop charts in late summer 1968, selling over one million copies, and earning Feliciano a gold disc. He also won two Grammy Awards for Best New Artist Of The Year and for Best Pop Song Of The Year in 1969.