Delson was born in Los Angeles, California and was raised Jewish. He graduated from Agoura High School in 1996 and formed Xero with Mike Shinoda, which would later become Linkin Park. He attended and graduated from the University of California, Los Angeles with a degree in communications but did not go to law school in order to pursue a career with Linkin Park.

While in college, Delson had to intern with a member of the music industry as a part of his career. He ended up working for Jeff Blue, an A&R representative at Warner Brothers Records. He told Blue about his band and in return for giving him demos to listen to he was offered constructive criticism. Blue is the man who found Linkin Park's future vocalist, Chester Bennington.

Before forming Xero, Delson's first instrument was the trumpet. His first band was called the Pricks, and he later played in a band called Relative Degree with his fellow Linkin Park bandmate Rob Bourdon. He met and roomed with bandmate Dave Farrell at UCLA.

Delson can usually be seen wearing a very large pair of headphones on stage. They are not connected to any sort of equipment via wires and there does not seem to be any plausible means for a wireless signal. The headphones are designed by Shinoda and himself and change with every Linkin Park release. Delson has never given a serious answer as to why he wears the headphones.

Some of his influences include Guns N' Roses, Metallica, Duran Duran, the Dave Matthews Band and Sunny Day Real Estate. He is often criticized for playing simple guitar parts and never performing solos. He has explained that this is due to the simplistic nature of the band, and the fact that he tries to make his guitar playing sound like a keyboard or strings to try to fit in with the hip hop and electronic sounds of the band.

He now resides in Los Angeles with his wife, Monica, to whom he has been married since September 16, 2003.

Gear: Brad Uses: PRS Guitars, Ibanez, Mesa Boogie, Marshall,and D'Addario strings.

Paul Reed Smith Custom 24 Guitar, orange. Ibanez RG 7 string guitar, black. Mesa Boogie Dual Rectifier amps Marshall Cabinets D'Addario 10 Gauge strings