In 2007, Willis joined the cast of The Biggest Loser as a trainer.  Willis was known for wearing dark sunglasses, camo pants, and a black sleeveless shirt .  Rarely smiling on the show, his motto was "there are no excuses".  Speaking to Nick Galvin of The Sydney Morning Herald , Willis said, "When it comes to the training and my ethos, Steve Willis and the screen persona 'The Commando' are the same person. I believe passionately in what I do".  Willis chose to depart The Biggest Loser after the tenth season aired in 2015.