He won the ISKA Super-Heavyweight Muay Thai World title on January 27, 1995, when he knocked out Wade Irwin in the third round.

Schuster defended the title five times, with knockout wins over Lee Hasdell, Valeri Savchenko, Kenny Gale, Branko Pavlovic and a decision victory over Jeff Roufus.

Schuster made his K-1 debut on September 7, 1997 at K-1 Grand Prix 97' Eliminations in Osaka, Japan, where he defeated Sadau Kitsiongrit by decision.

He later faced Andy Hug on April 9, 1998 at K-1 Kings 98 in Yokohama, Japan but lost by Decision.

On August 7, 1998, Schuster participated in the first-ever K-1 event in the United States at K-1 USA Grand Prix 1998.