DeMartini was born on April 10, 1963 in Chicago, Illinois, the youngest of five children, all of them boys. He spent his early years in the suburb of River Forest, Illinois. The family later relocated to San Diego. DeMartini became interested in rock music due to the influence of his older brothers Bernard and James, whose band rehearsed in the family basement. His grandmother was also a musician of note, playing piano accompaniment to silent movies in Preston, Minnesota. DeMartini's mother bought him a guitar at his request when he was "around seven or eight years old". According to Warren, he struggled early on learning to play it due to the tuning pegs being cheap, causing the instrument to constantly fall out of tune. As a result, he became frustrated and smashed the instrument as he had seen Pete Townshend of the Who do onstage. As a result, that was the last guitar he would receive as a gift. At age 14, he had to get himself a job in order to raise the money to purchase a new electric guitar, a CimarLes Paul copy. The first song DeMartini learned was Sunshine of Your Love by Cream, which he learned by ear. Warren played his first concert with his band the Plague in front of a small crowd at San Diego's La Jolla High School at the age of 15. By this time he was emerging as one of the San Diego area's most talented and sought-after young guitar players. The first year he signed up, he won "Best New Guitar Player in San Diego" at Guitar Trader on Clairemont Mesa Blvd. He graduated from high school in 1981. DeMartini began taking classes at a local college, but in the first semester was invited up to Los Angeles to join Mickey Ratt; the band that would eventually become the highly successful 1980s metal band, Ratt.
Ratt
DeMartini replaced Jake E. Lee, who would be hired by Ozzy Osbourne in December 1982. When DeMartini was called up from San Diego to join RATT in Los Angeles, he lived with Lee to learn the songs on the band's first album, and each greatly influenced the other's styles. DeMartini's lead guitar became one of Ratt's most recognizable aspects, and he would co-write several of the band's best known songs, including "Round and Round", "Lay It Down", "Dance", and "Way Cool Jr.". Ratt would ultimately become one of the top-selling and most popular metal acts of the decade, issuing four consecutive platinum albums and one EP in the 1980s before disbanding in February 1992.
Post-Ratt and Returns
After Ratt broke up, DeMartini had a short stint with the band Dokken before briefly becoming a touring guitarist for hard rock band Whitesnake in 1994. After that, he released two solo projects; the EP, Surf's Up! in 1995, and his only full-length album to date, Crazy Enough To Sing To You in 1996. Ratt re-united in 1996 and released two albums, Collage in July 1997, and a self-titled album in July 1999, which was a critical and commercial failure. In 2003, DeMartini was hired to replace guitarist Doug Aldrich in the band Dio but after several rehearsals he decided to leave the band due to musical differences with band leaderRonnie James Dio. Ratt reformed again in 2007 and began a tour in the summer of that year. In March 2018, it was widely rumored that DeMartini had lost interest with continuing forward with Ratt due to ongoing problems within the band. In July 2018, Ratt stated that DeMartini would no longer be involved with the current touring line-up as "he didn't want to go out there anymore."
Technique
VH1 labeled him as one of the ten most under-rated "hair metal" guitarists of the 80's. His playing often incorporates 4 note per string passages, which is still fairly unorthodox and some chromatic runs give DeMartini an almost jazz fusion sound for some solos. Along with that, his playing includes fast minor scales and wide vibrato. Warren will sometimes use finger vibrato, similar in style to George Lynch. This technique features moving the finger/wrist rapidly back and forth along the length of the string to alter the pitch, as opposed to bending the string.
