A native of Alcoi, at the age of 24 Montllor moved to Barcelona, where he was a member of various independent theater groups, including the CICF, and later with Núria Espert and Adrià Gual.

[citation needed] Montllor was known for his deep voice and his histrionic on-stage manners, and went on to become one of the most talented members of the Nova Cançó movement, albeit one of the least popular.

As a result of the tributes paid to him by internationally renowned artists such as Miquel Gil and Pascal Comelade, his work has received increased attention from music lovers in the last few years.

Montllor's gift for acting led to him being cast alongside Lola Gaos in José Luis Borau's Furtivos, one of the most important films in the history of Spanish cinema.

In 2005, on the tenth anniversary of his death, a series of tributes and celebrations in honour of Montllor took place throughout the Catalan countries.