Dio is a heavy metal band led by vocalist Ronnie James Dio, who formed it in October 1982 after leaving Black Sabbath. In an interview that is available on the special edition re-release of Holy Diver, Ronnie states that he never intended to begin a solo career. His intention was to just form a new band, with fellow former
Black Sabbath member drummer Vinny Appice, but Dio just became the band's name by accident, for he was well known, and it just sounded good to name the band Dio at
the time. In addition to Ronnie on vocals and Keyboards originally, and Vinny Appice on Drums, the band featured Vivian Campbell who played guitar; and Jimmy Bain, bass.
In May 1983 they released their debut album Holy Diver, on which Ronnie sang and played keyboards. To avoid having the vocalist stuck behind a keyboard in concert, the band recruited keyboardist Claude Schnell.
Now a quintet, they released The Last in Line on July 2, 1984, followed by Sacred Heart on August 15, 1985. Several songs were recorded during the tour for that album; they were released along with the studio-recorded "Time To Burn"
on the Intermission mini LP.
In 1986 Vivian Campbell left the band to join Whitesnake and was replaced by Craig Goldy. On July 21, 1987 their fourth album Dream Evil was released. After Dream Evil the entire Dio band was reconstructed introducing among other new musicians 19 year old guitarist Rowan Robertson. The new band released the album Lock up the Wolves. After this album Ronnie reunited with his former bandmates in Black Sabbath. The reunion was shortlived producing only one album. After this Ronnie James Dio reassembled the Dio band. At this time the guitarist Tracy G became a member of the band. During this era the band made the albums Strange Highways, Angry Machines and Inferno - Last in Live.
Goldy returned in 2000 for Dio's eighth studio album, Magica, but subsequently left before completion of Dio's ninth effort,
Killing the Dragon, which was released in 2002 through Spitfire Records. Doug Aldrich was the guitarist on Killing The Dragon. Goldy returned once more to Dio in the summer of 2003. In 2004 Dio released their tenth studio album, Master of the Moon on September 7, 2004 in America through Sanctuary Records, and on August 30, 2004 in Europe through SPV Records. The album features multi-instrumentalist Jeff Pilson (ex-Dokken) on bass duties. Pilson had earlier played with Dio in the 1990s.
2005 saw the release of the Dio live album Evil or Divine - Live In New York City, which featured the same show that was released on DVD in 2003. Dio has claimed he did not have much input on this release, as he had already left the label that released it. Dio
toured South America, Japan, Europe, and Russia in 2005. His fall tour is titled "An Evening With Dio" and is slated to feature a regular set, and then a second set of the
band playing his 1983 album Holy Diver in entirety. The band is purportedly going to film a date from this show in Russia for future DVD release. The audio
of this performance, a double CD named "Holy Diver Live" has been released in April 2006.
A new studio album is widely expected to be released in mid-2006.
In 1999, Dio appeared in an episode of South Park titled Hooked on Monkey Phonics. The band appears performing Holy Diver at an elementary school dance.