[4] In 1950, at the age of fifteen, he composed his first melody titled Nunca en el Mundo (Never in the World), of which twenty-one versions in different languages have been recorded to date.

[8] In 2011, Manzanero became President of and one of the main directors of the Asociación Nacional de Autores y Compositores (Mexican National Association of Authors and Composers).

[9] His work has been performed by singers such as Tito Rodriguez, Frank Sinatra, Elvis Presley, Shirley Bassey, Andrea Bocelli, Raquel Bitton, Tony Bennett, Laura Pausini, Alejandro Fernández, Perry Como, Luis Miguel, Franck Pourcel, Paul Mauriat, Ray Conniff, María Martha Serra Lima, Mina, Claudio Nicoletti, Raphael, Roberto Carlos, Christina Aguilera, Dionne Warwick, Manoella Torres, Marco Antonio Muñiz, Angelica Maria, José José, Tania Libertad, Lucero, Cristian Castro, and Il Divo, Carmen París, as well as with pianist Raúl di Blasio and others.

[clarification needed] He participated in numerous radio and television shows, recorded more than thirty albums, and composed the musical scores of several[vague] movies.

During the fifty years of his musical career, Manzanero gave performances all over Latin America, particularly in São Paulo (Brazil), Buenos Aires (Argentina), El Metropolitan (Mexico), the Teresa Carreño Theater of Caracas (Venezuela), Madison Square Garden (New York), and many other cities in Europe and Asia.

[7] His most famous songs include Voy a apagar la luz (I'm Going to Turn Off the Lights), Contigo Aprendí ( With you I Learned... ), Adoro (I Adore), No sé tú (I don't know if you...), Por Debajo de la Mesa (Underneath the Table) Esta Tarde Vi Llover (English version "Yesterday I Heard the Rain"), Somos Novios (English version "It's Impossible"), Felicidad (Happiness) and Nada Personal (Nothing Personal).