Brad Delson

Delson was born and raised in Agoura Hills, California. He attended Agoura High School with his friend, Mike Shinoda. Delson played the trumpet, and later began playing the guitar when he was 12 years old. He enjoyed listening to Guns N' Roses and Metallica. He played in the rock band Relative Degree with drummer Rob Bourdon, but the group disbanded after their first live show.

Delson attended UCLA, where he was roommates with bassist Dave Farrell for three years. He majored in communication studies, and later interned for Jeff Blue, then the vice president of A&R for Zomba Music. Blue shared his insight and experience on the music industry with Delson, while also giving him constructive feedback on musical projects. Delson graduated with a bachelor's degree in communication studies from UCLA in 1999. He considered attending law school after graduation but instead pursued a career as a professional musician.

Linkin Park

Delson, alongside Mike Shinoda and Rob Bourdon, founded Xero, the earliest incarnation of Linkin Park, in 1996. The band soon recruited vocalist Mark Wakefield, bassist Dave Farrell, and turntablist Joe Hahn. After Wakefield left Xero, Delson turned to his former boss Jeff Blue from Zomba Music to help find a replacement. Blue introduced the band to Chester Bennington, who successfully auditioned and became the band's full-time vocalist. Blue later became the vice president of A&R for Warner Bros. Records, and helped the band sign a record deal.

Delson played guitar on all eight of Linkin Park's albums. He also played bass on Hybrid Theory when Farrell temporarily left Linkin Park to tour with another band. After the release of Hybrid Theory, Delson was closely involved with the production and creative direction of Linkin Park's sound alongside Shinoda. The two co-produced The Hunting Party (2014) and One More Light (2017). While working on The Hunting Party, record producer Rick Rubin encouraged Delson to showcase his guitar playing by including more guitar solos compared to the band's previous albums. Delson commented on the new approach, "On the last few records I certainly played guitar in the studio, but I'd been focusing on other instruments… But these songs are all about rediscovering the guitar and having a lot of fun with it." He also oversaw the band's business operations, including their marketing and finance, alongside bandmates Farrell and Bourdon.

Delson and Linkin Park entered a seven-year hiatus following the sudden death of Chester Bennington in 2017. The band announced their reunion with new members in September 2024, and the band's eighth album, From Zero, was released in November, which Delson co-produced. Delson later revealed that he would not be joining the band on tour, preferring to work in the studio and behind the scenes. Alex Feder performs in his place, but Delson remains an official member of the band, and states that he has not ruled out a return to touring in the future.

Delson married Elisa Boren in September 2003. The couple bought a home in Los Angeles' Beverlywood neighborhood in 2022.

He was the keynote speaker at his alma mater UCLA's College of Letters and Science commencement ceremony on June 12, 2009, in Pauley Pavilion.

Delson is Jewish.

2004 – Delson and his wife established the Delson Scholarship Fund at UCLA, which annually awards four-year scholarships to extraordinary students from Huntington Park.

2005 – Linkin Park established Music for Relief, a non-profit organization founded to aid victims of world catastrophes and combat global warming. Since its founding, Music for Relief has raised almost three million dollars, helping victims of the South Asian tsunami, Hurricane Katrina, and the Southern California wildfires.

2005 – Signed on as an official supporter of Little Kids Rock, a nonprofit organization that provides free musical instruments and instruction to children in underserved public schools throughout the United States. Delson has personally delivered instruments to children in the program and sits on the organization's board of directors as an honorary member.