Esther Ferrer began her artistic career in 1967 by joining the Zaj group (1964-1996), made up of Walther Marchetti and Juan Hidalgo. Highly active through the mid-1970s, the collective organized numerous concerts, happenings, publications and installations. The movement, very similar to Fluxus, was however less spectacular: it based its art on minimalist gestures and everyday objects, and was inspired by the work of John Cage and Marcel Duchamp. After 1967, Ferrer was invited to prestigious festivals for her real-time, non-improvised performances. She wrote scripts, like sheet music with notes and drawings; these measured gestures were organized in a poetic, musical fashion, as in Canon para 4 Sillas, 1 mesa y 1 ventilador (Canon for 4 chairs, a table and a fan) at the Wilhelm-Hack Museum in Ludwigshafen, Germany in 1996. Starting in the 1970s, she began working in photography and drawing, and created canvasses based on a pre-determined plan, assuring continuity between her performance and visual work. In both her installations and her performances, she uses everyday objects in a given space to create absurdist situations.

In the performance Las Cosas (performed since 1985), the seated artist places various objects on her head, such as a picture frame, and carefully balances them there. For her unusual constructions, she carefully establishes an ephemeral order. Chairs, toys, envelopes, suitcases are re-purchased or found, replaced and transformed each time the installation is created, as in real life, thus marking the passage of time. One finds this dimension in several of her pieces, such as the famous Autoretrato en el tiempo (Self-portrait in Time, 1981-1999), a photographic portrait in which one half was taken at a different time than the other. Ironic and austere, her art has often been described as a particular kind of minimalism, incorporating rigor and lunacy.