Her family moved to Cataño and later to Santurce, a section of San Juan, where she finished her primary and secondary education. She was a student at Santurce Central High School when she auditioned and participated in school productions of "The Magic Flute", "Il Trovatore", "Rigoletto", "Lucia di Lammermoor" and "Aida" (Ms. Rivera believes these were the only operas ever produced by a high school anywhere in the world). She delighted audiences in Puerto Rico with her soprano voice in concerts which she organized. She planned to use the money obtained from these concerts to pay for her studies at the Juilliard School of Music in New York City.
In 1945, she was given the role of Adele in the musical "Rosalinda", a Broadway version of Johann Strauss II's Die Fledermaus. Rivera traveled to France and Germany with the production. That very same year she made her operatic debut as Rosina in "The Barber of Seville" by Gioachino Rossini at the New Orleans Opera.
In 1954 Rivera was featured as a guest singer in Name That Tune. In 1956, she performed at the Theater of the University of Puerto Rico and one of her back-up singers was a young fellow Puerto Rican by the name of Justino Diaz, who would someday also become a renowned opera singer. That same year Rivera was presented with a special recognition by the Government of Puerto Rico.
In 1959, Rivera returned to New York where she had a weekly radio show at WHOM. She traveled regularly between New York and Puerto Rico, in Puerto Rico she participated in the IV Pablo Casals Festival.
In 1993, Rivera earned her Doctorate Degree in Humanities from the Catholic University of Ponce and in 1996 she was bestowed with a Honoris Causa from Lehman College.