Born in Barbacoas, Aragua, he was the younger brother of the singer and composer Simón DÃaz.
He played professionally under the name Joselo.Initially, Joselo tried to emulate his older brother, although the ease of doing jokes about the daily life of the Venezuelan people set the course of his artistic career.
Joselo debuted on the popular sitcom Radio Rochela in 1959, aired by Radio Caracas Televisión, until it agreed on a long-term arrangement to keep him at the network by making him producer of his own weekly show, El Show de Joselo (1964–1972, 1981), which later was broadcast on Venevisión and was renamed Humor con Joselo (1973–1980, 1984–1993).
For nearly three decades, Joselo developed a significant number of characters in his weekly sitcom, effectively creating stereotypes and popular codes, conveniently remodeled and refined, achieving a deep approach to the lower and middle classes.
Among his most popular characters are El Pavo Lucas, Madam Cosmetic, El Adeco y el Copeyano, El Dr.