Rivero also organized the world's first known Walk-A-Thon, to raise money for the Liga Puertorriqueña Contra el Cáncer (the Puerto Rican League Against Cancer).
As a young man he learned to play various musical instruments, among them the piano, the guitar and the mandolin, under the tutelage of Amelia Maestú y Jorge Rubiano.
After witnessing a comedy by Cuban comedian Leopoldo Fernández also known as "Tres Patines", Rivero adopted the idea of creating a comical "Afro-Puerto Rican" character.
[1][7] Together with Torregrosa, Rivero founded "La Farándula Bohemia", a theatrical company in which he was able to develop the character "Diplo" and make him known to the public.
During World War II, Rivero and his acting troupe, the "La Farándula Bohemia" (Bohemian Show-business), traveled to the United States military bases in which Puerto Rican troops were stationed and not only did he entertain the men, but he also accepted and delivered mail to the families of those whom he met overseas.
[5] Puerto Rican industrialist Angel Ramos, owner of WKAQ Radio, signed an exclusive deal with Rivero to broadcast "El Tremendo Hotel" via the airwaves.
[9] Among the many Puerto Rican artists who began their careers in "El Tremendo Hotel" were Luis Vigoreaux, Miguel Ángel Álvarez[10] and Sylvia Rexach.
[1][5][4][6] Rivero produced and acted in various theatrical productions in Puerto Rico among them Mosquilandia (Mosquito Land), El Príncipe Wele-Wele (Prince Wele-Wele), A Mi Me Matan Pero Yo Gozo (They can kill me, but I'll enjoy it), Ese Niño Es Mio (The child is mine), Hay Que Defenderse (One must defend himself), La Familia del Lío (The family of problems) and El Tremendo Hotel, however his success was not limited to the theater and radio.
[13][6] In Cuba, Rivero participated in the movie Una Gallega en la Habana with Niní Marshall, however it was in Puerto Rico that in 1953, he played the lead role of "Pepe" in what is possibly the best motion picture ever made in the island, Los Peloteros ("The Baseball Players") (with Puerto Rican actress Míriam Colón co-starring as his wife, Lolita) under the direction of Jack Delano.
[14] The movie, which is based on a real-life story, is about a man (Pepe) who, despite the fact that no one takes him seriously, is willing to coach a group of very poor children and help them raise funds for their baseball team.
[14][4] Rivero wrote more than 3000 scripts for radio, theater, television and motion pictures and was the author of ¿Por qué se ríe la gente?
[15] Rivero also defended the victims of injustice during student revolts at the University of Puerto Rico, led the first actors' strike on the island, and was the first producer/personality to actively combat racial prejudice on Puerto Rican television, incorporating blacks in his television shows; first in "La Taberna India" (Juan Boria), followed by Rita Delgado and Dixon as cast members of his "La Farándula Corona".
[1] Rivero was buried at Cementerio Santa María Magdalena de Pazzi, San Juan, Puerto Rico, and a state of national mourning for two weeks was declared on the island.