He established a handkerchief and lace products factory (and ran a numbers game operation as a side occupation), and became a successful businessman.
Since he was tall for his age (and had a booming bass voice, which was the deepest one of any local radio personality at the time he became a broadcaster), Gilbert could sneak in clubs at an age as early as thirteen years-old, which allowed him to visit relatives in New York City and sneak into live presentations by Tommy Dorsey and Xavier Cugat (who caught him playing bongo drums onstage with the band unsupervised once, and later became a friend).
Gilbert would later make solo trips to Cuba at the age of sixteen (1943), in search of local acts such as the Orquesta Casino de la Playa and Miguelito Valdés.
Gilbert became a cultural reference himself in another plena, Daniel Santos' version of "La Máquina" ("The Engine"), a song about the existing train route between San Juan and Ponce (for which Mayagüez was the midway point) in the lines: "Mamery le puso un disco/Y la máquina bailó" ("Mamery played a record, and the engine danced").
The most notable of these performers was Raphael, who stayed at Gilbert's home while in Mayagüez, while the house was mobbed by screaming fans who even climbed to the roof to get a glimpse of their idol).
(Individual broadcasts would be rerun previously recorded at different times in different stations, but the daily airings would be done live at 5:00 pm, AST).
He moved WTIL-AM and his media publicity firm, Mamery Publicidad, to the new facility, and eventually gave control of day-to-day operations to his children.
In the late 1970s and early 1980s he expanded his reach to the rest of the country by hosting nostalgia shows, in which he'd play videos and short films by Puerto Rican and American artists (and, inevitably, one by Carlos Gardel in every broadcast).
To the surprise of many, Gilbert sold the station, not before ensuring a reserved spot in its programming to continue broadcasting "La Discoteca del Recuerdo" from his home studio.
A lifetime of smoking had Gilbert develop emphysema, which only slowed his output, although he would complain about respiratory distress in his last days.
On the early morning of March 30, 2003, Gilbert woke up at 3:00 am (AST) in his Mayagüez home, apparently showing no symptoms of poor health at the time.
Besides leaving behind an enormous multimedia collection and a clan with strong ties to Puerto Rico's media industry, Gilbert Mamery's uncompromising standards of quality and business acumen have shaped the career of various local performers.