[2] Gabriel Varga was born in Toronto, Ontario and spent part of his childhood in Australia and New Zealand before settling in Victoria, British Columbia, in 1999.

[4][5] Varga began competing as an amateur in 2006 at the age of twenty and, after amassing an 8–0 record by 2008, spent three months training in Thailand at Eminent Air, Fairtex, Por Pramuk and Sinbi Muay Thai.

[6] Upon his return to Canada, he was given the chance to fight for his first title and he outpointed Carlos Garcia to take the ISKA Amateur North American Light Welterweight (-64.5 kg/142.2 lb) Oriental Championship.

[6] He then stopped Chuck Mady with body shots in the first round for the ISKA Amateur Canadian Super Lightweight (-62.3 kg/137.2 lb) Oriental title on August 15, 2008.

[7] Now a national and continental belt holder, Varga faced Joe Concha in an ISKA super lightweight amateur world title match in his hometown of Victoria on January 24, 2009.

[10] Following this, Varga moved back up in weight to challenge for the ISKA amateur light welterweight world title against Devon Henry in Victoria on July 20, 2009.

[11] In his final bout as an amateur, he took a unanimous decision over Nathan Smandych on October 3, 2009, in Victoria to defend his ISKA light welterweight strap and bring his record to 15–0.

In his pro debut on December 12, 2009, he travelled to Flushing, New York, United States and defeated local fighter Omar Ahmed by unanimous decision.

[6] A rematch with Greskiewicz was set for December 3, 2010, at The Warriors Cup XIII in Lincroft, New Jersey, US but fell through when Justin was injured in a motorcycle accident.

[23][24] After a year out of the ring, he signed with K-1 and made his promotional debut at the K-1 World Grand Prix 2012 in Los Angeles in California on September 8, 2012, against Lerdsila Chumpairtour.

He dominated Abdellah Ezbiri en route to a unanimous decision win in the quarter-finals, but lost to the eventual champion Yuta Kubo by the same margin in the semis.

[27][28] Varga was set to face Shane Oblonsky at Glory 11: Chicago - Heavyweight World Championship Tournament in Hoffman Estates, Illinois, US on October 12, 2013.

[31] He was then set to make a defence of his WKN title for the first time against Jessy Petit-Jean in Belgium on November 9, 2013, but the bout was cancelled for undisclosed reasons.

[43] Varga would rebound from this loss with a decision win against Lu Yichen at Hero Legends[44] and a second-round TKO of Roberto Gheorghita at Bellator Kickboxing 8: Florence.