Trennon was named the Canadian National Halfpipe Team Head Coach in 2011. Before that, he and a group of athletes, including Sarah Burke, Mike Riddle, Rosalind Groenewoud, and Justin Dorey, formed their own, athlete funded, unofficial "Canadian Team” that operated before Halfpipe Skiing's Olympic inclusion opened up National team funding channels.
As an athlete, Trennon competed in the 1999 and 2001 World Championships for Canada, and the 2002 Olympic Games for Australia, and also competed in 53 World Cups overall.
Trennon was a part of the original “new school skiing” movement, which featured performances in ski films such as “13” and “The Supershow”. He has competed at an International level in a wide variety of disciplines, including: Moguls, Halfpipe, Alpine Racing, Slopestyle, Ski Cross, Mt Bike Downhill, Enduro Motocross, Surfing.
Under Trennon's tutelage, Mike Riddle won a silver medal in men's ski halfpipe during the inaugural event at the Sochi Olympic Winter Games. Trennon's athletes have won numerous World Championship titles, X Games titles, World Cup overall titles, and World Cup medals showing with Cassie Sharpe’s continued success as a medalist at the 2019 World Championships in Deer Valley, USA.