As a teenager, Reyna lived in the city of Monterrey, Nuevo León, and shortly thereafter, moved to Houston, Texas, where he worked as a bricklayer.
Later, in Saltillo, Coahuila, Reyna began his musical career by writing songs, singing, and playing the bajo sexto (very similar to a twelve-string guitar)..
In 1957, along with Juan Peña, Cornelio formed the duet Dueto Carta Blanca, frequenting the Cadillac Bar, where many musicians from the region of northern Tamaulipas and southern Texas met.
From there, they went out to play at different nightclubs in Reynosa, but Cornelio's goal was to do it professionally, taking advantage of his great ability to perform the bajo sexto.
One day, when Juan Peña decided to take leave from the Dueto Carta Blanca, they invited Ramón to join and present himself as the new companion to Cornelio.
Throughout his life he maintained contact with his former musical partner, Ramón Ayala, who had formed the group Los Bravos del Norte.
Cornelio was still relatively young, and although his fame was no longer the same as it had been a few years prior, in the southern region of Texas and northeast of Mexico he continued to have a large and faithful following.