A veteran of the sport for 25 years, Mock is known for his toughness and has only ever been stopped once in his career. Born in the Democratic Republic of the Congo, Mock made his professional debut on 11 May 1991, fighting across several countries in Africa and winning his first seventeen fights. In 2000 he fought in Europe for the first time, where he would later become a Danish citizen.
Despite scoring a knockdown against Haye in the second round, Mock was stopped in the fourth.
On 26 September 2003, he fought future world champion David Haye at cruiserweight. A fight against another future world champion came against Lucian Bute on 16 May 2006, which ended in a twelve-round unanimous decision victory for Bute. On 3 November 2006, Mock won his first major regional championship—the vacant European Union super-middleweight title—when he defeated Franck Mezaache via fifth-round corner stoppage. Having vacated the title after one defence, Mock won it twice more on 14 March 2008 and 30 January 2010, against Mouhamed Ali Ndiaye and Giovanni De Carolis respectively.
