Ernesto Rodrigues was born in Lisbon on August 29, 1959, and began studying music at age seven. In 1973 he entered the Academia de Amadores de Música before moving on to the Conservatório Nacional, where he trained in violin and composition. As a teenager in the 1970s he was drawn away from the conservatory's own repertoire toward free jazz, the post-war avant-garde of Ligeti and Stockhausen, and the experimental composition of Morton Feldman and John Cage, a mix that set the direction of everything he has done since.

His earliest documented recording, the duo album Self Eater And Drinker with electronic musician Jorge Valente, was cut at Xangrila studio in Lisbon in February 1999 and released on the small label audEo, with Rodrigues playing violin, prepared violin, and live signal processing. Within two years he had founded the vehicles that would define his career: the Variable Geometry Orchestra in 2000, a large-scale improvising ensemble with a constantly shifting roster drawn from Lisbon's improvised-music community, and, in 2001, Creative Sources Recordings, a label conceived to document his own work and that of other Portuguese and Spanish improvisers working outside the commercial mainstream. Creative Sources' first release, catalog number CS 001, was Multiples (recorded December 27, 2000, at Tcha Tcha Tcha Studios, Lisbon, and dedicated to the British free-improv drummer John Stevens), a trio with cellist Guilherme Rodrigues, Rodrigues's son, and percussionist José Oliveira. That single release established, in one stroke, both the label and the most durable musical partnership of his career: Guilherme Rodrigues has appeared on the great majority of his father's recordings ever since.

Creative Sources grew far beyond a personal outlet. What began as a Lisbon-focused imprint expanded through the 2000s and 2010s to release electro-acoustic and free-improvised music by an international roster that has included Radu Malfatti, Axel Dörner, Gino Robair, Udo Schindler and Raed Yassin, among hundreds of others; the Discogs database lists more than 2,600 releases under the Creative Sources name, making it one of the most prolific active labels anywhere in free improvisation. Rodrigues also organizes CreativeFest, an annual festival held every November at O'Culto da Ajuda in Lisbon that has run for more than a dozen editions, presenting ensembles from duos to full-orchestra configurations and generating a steady stream of live recordings for the label's catalog, including the Variable Geometry Orchestra's own Mare Tranquillitatis (2019), taped live at CreativeFest XII in November 2018 with a personnel of more than thirty musicians.

Alongside the Orchestra, Rodrigues has led or co-led a rotating set of smaller working groups built around the same aesthetic of restraint and close listening, among them Suspensão, an octet whose 2011 debut recording (Tcha3 studio, Lisbon, June 2010) paired his viola with Nuno Torres's alto saxophone, prepared electric guitar, tuba, toy piano, and electronics; the International Klein Blue (IKB) ensemble; String Theory; Isotope Ensemble; Octopus; and Diceros. He has also built an extensive catalog of duos and small groups with visiting international improvisers, expanding through the 2010s and continuing into the present with figures including violinist Biliana Voutchkova and pianist Magda Mayas (The Afterlife Of Trees, 2017), vocalist Ute Wassermann (L'âge De L'oreille, 2023), and, on Not Bad (2023), the veteran German free-jazz drummer Günter "Baby" Sommer, alongside Guilherme Rodrigues and saxophonist Gonçalo Mortágua. As recently as 2026 he recorded Dots And Dashes with the Greek reed player Floros Floridis, evidence of a pace of work that has not slowed after more than two decades running the label.

From 2018 Rodrigues also became a recurring visitor to Berlin's improvised-music scene through a trio and quartet with Israeli guitarist and banjoist Ido Bukelman and Guilherme Rodrigues, documented on the digital-only Creative Sources releases Exodus and Mosaic (both 2018) and Straw (2020, adding double bassist Antti Virtaranta), a partnership that grew out of Bukelman and Guilherme Rodrigues's own 2017 Berlin duo recording. In January 2017, back on his own label's home turf, Creative Sources released Black Mynah, a duo album by Israeli saxophonist Albert Beger and bassist Shay Hazan recorded at the Mishkanot Sha'ananim Studio in Jerusalem. Rodrigues does not play on the record; Discogs credits him as executive producer, album-wide, alongside Beger and Hazan's own production credits, reflecting his label's role in bringing the session to release rather than a playing role in the session itself.

Rodrigues's playing and his label share the same governing idea: that silence and the space around a sound carry as much weight as the sound itself. He has described improvisation in terms of breathing, "sound as an exhalation, silence as the corresponding inhalation, a necessary rest between sounds pushed out into being," and his viola and violin work, built on extended techniques, preparations, and micro-tuning, deliberately works against a conservatory-trained string player's instincts toward projection and vibrato, favoring instead a bowed tone so quiet it can sound like breath moving across the strings. That aesthetic, sometimes summarized by critics as an emphasis on texture, timbre and gradual development over density or event, became the house style of Creative Sources itself: reviewers have called the label, under Rodrigues's direction, "an icon of free music, especially music preoccupied with silence and space." His influence on the European free-improvisation scene runs through two channels at once, as a working violist heard on hundreds of recordings across four decades, and as the founder of a label and festival that gave several generations of improvisers, Portuguese and international, a place to record and be heard.