He began training Muay Thai at the age of 22, and while he won the World Kickboxing Network (WKN) Intercontinental Super Welterweight (-72.6/160.1 lb) Championship as an amateur, the beginnings of his professional career were fought in relative obscurity.

Having built up an extensive record with an impressive knockout ratio fighting in smaller events in Suriname and the Netherlands, he was recruited by the It's Showtime promotion at twenty-nine years of age.

[3][4] On September 25, 2011, Ristie defeated William Diender via unanimous decision in the tournament reserve bout of the BFN Group & Music Hall presents: It's Showtime "Fast & Furious 70MAX" in Brussels.

[5] He followed this up with a technical knockout defeat of Jonay Risco at Street Culture, Fight Club Group & Canary Kickboxing Federation presents: It's Showtime 53 on November 12, 2011, in Tenerife, Spain.

Having dominated Risco throughout the fight, Ristie floored the Spaniard with a left hook in round three and, while he was able to make it back to his feet, referee Joop Ubeda called a halt to the contest.

He began the fight by battering Drago with knees to the head and body and continued to put a one-sided beating on the Armenian throughout, winning a wide unanimous decision.

[11][12][13][14] On June 30, 2012, he KO'd Samir Djabba with a left hook in the first round, after 32 seconds, Music Hall & BFN Group present: It's Showtime 57 & 58 in Brussels.

[15][16][17] Then, in his third fight in as many months, he stopped David Calvo with a knee to the body in under a minute at Street Culture, Federación Canaria de Kickboxing & Fightclub Group present: It's Showtime 59 in Tenerife on July 21, 2012.

[51] Riding the wave of momentum that saw him dethrone kickboxing's all-time greatest, Ristie continued his rich vein of form in the final against Robin van Roosmalen, dropping the Dutchman towards the tail end of round one before putting him away in two.

[62] Andy Ristie knocked out Ky Hollenbeck thirty-five seconds into round one, stunning his American opponent with a jab before putting him away with a left hook.