Robert Siers Cavallo is an American record producer, musician, and record executive renowned for his profound influence on modern rock and alternative music. With over 130 million albums sold worldwide and multiple Grammy Awards to his name, Cavallo has shaped the sound of an entire generation. He is best known for his work with Green Day—most notably their albums Dookie, American Idiot, and Saviors—but his versatile production style has extended to artists across the musical spectrum, including LINKIN PARK, My Chemical Romance, Paramore, Goo Goo Dolls, and Alanis Morissette.

Born in Washington, D.C. and raised in Los Angeles, Cavallo's passion for music was sparked by his father's Beatles collection. He graduated from the University of Southern California in 1985 and studied music further at the Dick Grove School. He began his career in the studio world under George Massenburg, then joined Warner Bros. Records as an A&R executive, where he signed Green Day and the Goo Goo Dolls. Over the years, Cavallo held major leadership roles in the music industry, including serving as Chairman of Warner Bros. Records and Chief Creative Officer of Warner Music Group.

In addition to his skills as a producer, Cavallo is a multi-instrumentalist and occasionally performs or contributes musically to the records he produces. His songs and albums have consistently topped charts, earned platinum certifications, and influenced generations of listeners.

Rob Cavallo has played a critical role in shaping ONE OK ROCK's modern international sound. He first worked with the band on their album Luxury Disease, serving as the executive producer and contributing to songwriting, arrangement, and production across multiple tracks including Save Yourself, Vandalize, So Far Gone, and Let Me Let You Go. His involvement helped elevate the album's production quality to match global standards while preserving the band's emotional core.

Their creative partnership deepened with the release of {albumDetox}, where Cavallo returned as a lead producer. He oversaw recording sessions, contributed additional guitar work, and helped arrange and produce many of the album's most dynamic tracks, including {songNASTY}, {songTropicalTherapy}, and {songPartysOver}. His work with the band spans songwriting, sonic experimentation, and instrumental guidance.

Though he is not formally their manager, Cavallo has become one of the band's most important long-term collaborators and advocates in the U.S. music industry. His influence is widely recognized as instrumental in helping ONE OK ROCK cross over into the Western rock mainstream without compromising their artistic identity.