Rowan Robertson took up guitar at the early age of five. Rowan Robertson's influences on the guitar were Steve Vai, Randy Rhoads, Jimi Hendrix and Eddie Van Halen.
Robertson got a good response from Dio and in late January or early February 1989 he was flown to Los Angeles for an audition with Dio. He was auditioned twice and right after the second audition he was invited to the band. The press-release of the joining was dated on July 18th, 1989 and the press was invited to see the guitarist on July 20, 1989 at Oliver's Pub in New York City.
The first Dio album he started working on was Lock up the Wolves together with Jimmy Bain, Vinny Appice and Jens Johansson. The band had started writing and recording when Jimmy Bain and Vinny Appice were fired from the band. They were replaced with Teddy Cook and former AC/DC drummer Simon Wright. Recordings do exist from the sessions with Bain and Appice but were never released. Lock up the Wolves was released in 1990, and the band embarked on a tour in support of the album.
Robertson stayed in Dio until Ronnie James Dio rejoined Black Sabbath in 1991. Dio and Robertson had been writing songs for an album to be released in May 1991. When the Dio band was put on ice - or more or less disbanded - Robertson started to work on an instruction video for guitar players. After it was released on Star Licks in July or August 1991, supposedly only in the USA - he teamed with vocalist Oni Logan (ex Lynch Mob) and drummer Jimmy Paxson (ex Triangle) and started to record on an album together on Atlantic Records.