Earning the envy of most other Floridan bands due to their "awesome equipment", Avatar was originally a five-piece, with Jon on drums and vocals, and Criss on guitar.

The band slowly drifted apart until Jon and Criss remained, and the two got jobs at "The Pit", a practice shack where they met Steve Wacholz.

When he got to the audition, Wacholz recognized Criss and Jon as part of the band who had impressed him so much at the high school show.

In late 2006, footage was released onto the internet of an early performance by Avatar at a gig in a Clearwater, Florida parking lot and was prominent in featuring an early version of the song "Holocaust",[5] which would later be released on Savatage's first album and a cover of Van Halen's "Eruption" and the latter's version of "You Really Got Me".

Jon and Criss were playing cards with their wives when they got a phone call and after initial tweaking, they finally arrived at Savatage.

During this time, the band hired Johnny Lee Middleton to replace Keith Collins on bass duties due to musical differences.

Savatage were finally getting exposure, but in 1986, the band released Fight for the Rock, a stab at mainstream success that was driven primarily by Atlantic.

On the resulting tour, Savatage supported Dio and Megadeth, but Jon had many conflicts with the latter's lead singer Dave Mustaine, who at the time was a serious substance abuser.

Jon altered the band's direction into a more progressive sound, and the resulting record was Gutter Ballet, released in 1989.

The official reason given was to concentrate on his side-projects Doctor Butcher and his Broadway-bound musical Romanov[9] as well as continuing co-writing Savatage material with his brother Criss and producer Paul O'Neill.

Jon hand-picked his Savatage replacement, former Wicked Witch lead vocalist Zachary Stevens and the band recorded their follow-up to Streets, Edge of Thorns in 1993.

For the first time, Savatage began to enjoy mainstream recognition, including increased radio play and a world tour.

Originally, Jon was to leave the band, then return as a lead vocalist on the follow-up record to Edge of Thorns.

[11] Around this same time, Jon was approached by one-time Savatage guitarist, Chris Caffery, who recorded with the band on Gutter Ballet.

Doctor Butcher played a couple of shows in the Tampa area in 1993, one of which included an appearance by Criss Oliva who joined the band on stage for a rendition of "Sirens".

Oliva has stated however that he was saddened about the success of the record, citing the fact that the same song was released by both bands, yet TSO's rendition became a bigger hit.

He was featured on the album WWF Full Metal in 1996, singing the song "We're All Together Now" with several WWE professional wrestlers as part of the Slam Jam.

[14] In 2001, after Stevens left the band citing family reasons, Oliva returned to provide lead vocals for Savatage's new album, Poets and Madmen.

Aside from a short-lived reunion at Wacken Open Air in 2015, Savatage had been mostly inactive since 2002, when the band went on hiatus following the tour cycle for Poets and Madmen.

After some speculation that they were reuniting in 2021 to record a new album,[15] Oliva confirmed in an interview with "80's Glam Metalcast" in March of that year that he and his Savatage bandmates Chris Caffery and Al Pitrelli had been working on new material together, and added that he would "love" to reform the band.

[16] In September 2023, Oliva suffered a spinal injury which postponed production of the upcoming Savatage album Curtain Call until early 2024: "I slipped on a wet marble floor and I fractured my T7 vertebra.

"[22] In October 2024, Oliva revealed that he was diagnosed with both multiple sclerosis and Ménière's disease and "[his] doctors are working with [him] to get healthy again."

As the result of his condition, he will not be joining Savatage for their first show in almost ten years at the Monsters of Rock festival in São Paulo on April 19, 2025.