Luján was born in Bogota, Colombia, while his parents, both actors, were on tour presenting a play, but he never obtained Colombian nationality.

His late brother, Alejandro Ciangherotti, ex-wife, Adriana Parra, wife Martha Mariana Castro, children Fernando, Vanessa, Cassandra, Fernando Canek, Franco Paolo,[3] granddaughter and son-in-law Vaita and Roberto Sosa, nephews Alejandro III, Alexis and Alan are also actors.

After appearing in more than eight films, mostly light comedies, he obtained a role in the telenovela Cuatro en la trampa at age twenty-three.

The next eighteen years, he alternated his film career with television, culminating with the worldwide famous production Los ricos también lloran.

After Mirada de mujer, he obtained significant roles in film, especially as the star of the film-version of Gabriel García Márquez's book No One Writes to the Colonel in 1999 (El coronel no tiene quien le escriba).