He joined Menudo in early 1987, at a time that the group's worldwide fame was still strong, although it had begun to wane. He was popular among Menudo fans, and was a member of a Menudo line-up that included Ricky Martin, Raymond Acevedo, Sergio Blass, Rubén Gómez and Robi Rosa. He sang the songs "Cuando Seas Grande" and "Y Te Veré (A Las Tres)" featured on the Spanish album Somos Los Hijos del Rock.
In 1991, Edgardo Diaz was accused by ex members of Menudo of sexual abuse towards Menudo members. In a May 1991 Univision Television Program Cristina Show, he refuted the allegations. Diaz has been the target of several sexual crime allegations by former Menudo members, Ralphy Rodriguez and Roy Rossello, who accused him of sexual abuse during a Brazilian reality show's transmission on October 21, 2014. 
Rodríguez became a born-again Christian, and released a gospel CD in 2001.
- González-Andino, Heriberto (May 8, 2008). "MDO y Menudo tras el mercado juvenil". El Diario La Prensa. New York, N.Y. p. 32.