Cozy Powell was born in Cirencester, Gloucestershire, England, and started playing drums at age 12 in the school orchestra, thereafter playing along in his spare time to popular singles of the day. The first band he was in, called the Corals, played each week at the youth club in Cirencester. At age 15 he had already worked out an impressive drum solo. The stage name 'Cozy' was borrowed from the jazz drummer Cozy Cole.
The semi-professional circuit was next, with semi-pro outfit The Sorcerers, a vocal harmony pop band. The late nights and usual on-the-road exploits began to affect his education, and Powell left to take an office job to finance the purchase of his first set of Premier drums. The Sorcerers performed in the German club scene of the 1960s. By 1968 the band had returned to England, basing themselves around Birmingham. Powell struck up friendships with fellow musicians like Robert Plant and John Bonham (both at the time unknowns in Listen), future Slade vocalist Noddy Holder, bassist Dave Pegg and a young Tony Iommi. The Sorcerers now became Young Blood, and a series of singles were released in late 1968–69. The group then linked up with the Move bassist/singer Ace Kefford to form The Ace Kefford Stand. Five recorded tracks are available on the Ace Kefford album 'Ace The Face' released by Sanctuary Records in 2003. Powell also began session work. Powell with fellow Sorcerers Dave and Denny Ball formed Big Bertha.
In 1972 Powell drummed for two tracks ("Hey Sandy" and "Martha") on Harvey Andrews' album Writer of Songs. By late 1972 he had joined up with the Ball brothers and singer Frank Aiello to form Bedlam, whose eponymous album was recorded for Chrysalis and released in August 1973. Eventually Powell abandoned Bedlam to record two singles including "Dance with the Devil", which reached No. 3 in the UK singles chart during January 1974. The song was his only solo hit in the United States, peaking at No. 49. The track featured Suzi Quatro on bass. Powell's second hit during 1974 was with "The Man in Black", which reached a respectable No. 18. Arrows front man Alan Merrill, also a RAK records artist, played electric bass on '"The Man in Black'" and the b-side '"After Dark." Jeff Beck's studio producer was Mickie Most and Powell soon found himself drafted into sessions for artists signed to Most's RAK label, including Julie Felix, Hot Chocolate, Donovan and Suzi Quatro. To cash in on his chart success the drummer formed Cozy Powell's Hammer in April 1974. The line-up included Bernie Marsden (guitar), Clive Chamen (bass), Don Airey (keyboards) and Frank Aiello (Bedlam) on vocals. Clive Chamen was replaced on bass by Neil Murray in the band in early 1975 for the RAK Rocks Britain Tour. "Na Na Na" was a UK No. 10 hit, and another single "Le Souk" was recorded but never released.
In 1975 he joined Rainbow. Powell and Ritchie Blackmore were the only constants in the band's line-up over the next five years, as Blackmore evolved the sound of the band from a neo-classical hard rock/heavy metal to a more commercial AOR sound. Rainbow's 1979 Down to Earth LP (from which singles "Since You Been Gone" and "All Night Long" are taken) proved to be the band's most successful album thus far; however, Powell was concerned over the overtly commercial sound. Powell decided to leave Rainbow, although not before they headlined the first ever Monsters of Rock show at Castle Donington, England on 16 August 1980. The festival was Powell's last show with the band.
After Powell left Rainbow he worked with vocalist Graham Bonnet (he too an ex-Rainbow member) on Bonnet's new project called Graham Bonnet & The Hooligans, their most notable single being the UK top 10 single "Night Games" (1981), also on Bonnet's solo Line Up album. For the rest of the 1980s, Powell assumed short-term journeyman roles with a number of major bands – Michael Schenker Group from 1981 to 1982, and Whitesnake from 1982 to 1985. In 1985 he started recording with Phenomena for their self-titled first album, which was released the same year, when he joined up with Keith Emerson and Greg Lake as a member of Emerson, Lake & Powell.
Powell worked with Gary Moore in 1989, followed by stints with Black Sabbath from 1988 to 1991, and again in 1994–1995. Between late 1992 and early 1993, Powell put together an occasional touring band using the old band name 'Cozy Powell's Hammer' featuring himself on drums, Neil Murray on bass, Mario Parga on guitar and Tony Martin on vocals and occasional rhythm guitar/synth module. The band performed throughout Europe and appeared on German television. Powell along with Neil Murray were members of Brian May's band, playing on the Back to the Light and Another World albums. Powell played with May opening for Guns N' Roses on the second American leg of their Use Your Illusion tour in 1993. The duo also served a spell with blues guitarist Peter Green in the mid-nineties. Powell briefly joined Yngwie Malmsteen for the album Facing the Animal in 1997. Powell's last recording session was for Colin Blunstone's The Light Inside, alongside Don Airey, which was released shortly after Powell's death. The final solo album by Cozy Powell Especially for You was released in 1998 after his death, and featured American vocalist John West, Neil Murray, Lonnie Park, Michael Casswell and others.
Powell had a fascination with fast cars and motorbikes, and raced for Hitachi on the UK saloon car circuit for a few months. He made headlines, when he appeared on the BBC children's programme Record Breakers, where he set a world record for the most drums played in under one minute, live on television.
Powell died on 5 April 1998 following a car accident while driving his Saab 9000 at 104 mph (167 km/h) in bad weather on the M4 motorway near Bristol.
Powell was dating a married woman who was having troubles with her husband. Upset, she phoned him on 5 April 1998 and asked him to come quickly to her house which was approximately 35 miles away. As he was making the drive to her house she phoned him again and asked "Where are you?" He informed her he was on his way and then she heard him say "Oh shit!" followed by a loud bang. Powell was ejected through the windscreen and died at the scene. According to the BBC report, at the time of the crash Powell's blood-alcohol reading was over the legal limit, and he was not wearing a seat belt, in addition to talking with his girlfriend on his mobile phone. The official investigation also found evidence of a slow puncture in a rear tyre that, it was suggested, could well have caused a sudden collapse of the tyre with a consequent loss of control of the car.
He was living at Lambourn in Berkshire at the time and had returned to the studio shortly before his death to record with Fleetwood Mac co-founder Peter Green. At the time of death Cozy had recently had to pull out of tour rehearsals with Yngwie Malmsteen, having suffered an injury in a motorcycle accident. One of his last phone calls, to his fanclub editor, was to express distress about this, but also enthusiasm of the then forthcoming Brian May tour. By that time, he had been the drummer on at least 66 albums with minor contributions on many other recordings. Many rock drummers have cited him as a major influence.
In October 2005 Powell made a "new" appearance on an album. Former Black Sabbath vocalist Tony Martin released a studio album (Scream), and on it is a track named "Raising Hell". This was a track Powell had recorded the drum track for when he and Tony were in Hammer in 1992, and gave to Tony for "future use". There are apparently as many as 19 additional drum tracks also recorded that could turn up in the future. Judas Priest guitarist Glenn Tipton has also released material recorded during the 1997 Baptizm of Fire sessions; this 2006 collection, entitled Edge of the World, was released under the moniker of Tipton, Entwistle & Powell in memory of John Entwistle and Powell.
New York drummer Ken Serio played a tribute to Cozy Powell on his highly acclaimed Through the Gate CD covering several songs from Cozy's instrumental solo albums including the Bernie Marsden penned "El Sid" from Cozy's Over the Top album.