"I don't want to be a passenger. I want to be someone who really makes an impact on this tournament," Cahill said.
Asked to describe himself in one word, Cahill didn't blink before replying, "fearless".
He could have settled on feared, for he's the Socceroos' all-time leading goalscorer and the one other nations most worry about.
He knows he doesn't just wear a number on his back - he carries a target and Cahill is fully prepared for the likely rough-house tactics coming his way.
"I have played in the roughest and biggest leagues in the world," he said.
"If it's playing pure football I can do that.
"If it's mixing it with the big shots, if anything that plays into my hands because I really like a physical game.
"And I also really like to be the one that dominates when I come onto a football pitch."
He's a marksman who relishes being a marked man.
"When any defender plays against me, they will have to stand up really close to physically try and bully me," Cahill said.
"In the end, they give me my five yards that I have earnt throughout my career of playing as a footballer, which ends up pretty much being the back of the net.
"There's not really a lot of pressure on me because whether I play 20 minutes or 90 minutes, I know I will affect the game.
"If I'm not on the football pitch, the fans will be sitting on the edge of their seats waiting and willing. I feel that and I know the expectation is big but it's a great feeling.
"Coming on knowing that defenders are scared of me ... that is something that I know.
"If I really put my head down and really try and affect this Kuwaiti team or the Omanis or any team - if I don't score, then whoever is near me or around me will score or reap the benefits of me being on the pitch."
Cahill hopes his confidence is contagious as the Socceroos prepare for Asian Cup group matches against Kuwait in Melbourne, Oman in Sydney and Korea Republic in Brisbane.
He's bullish about Australia's prospects given the mantra of coach Ange Postecoglou.
"The best thing I love about it is his intent," Cahill said of Postecoglou.
"To put a real firm Australian feel of keeping the ball, playing football, believing, playing from the back.
"He always says 'don't take a step back, because we're Australians'.
"And that is where you get the belief.
"For these (Socceroos) youngsters to believe in themselves, which is what we're tapping on, they might surprise themselves.
"I don't get surprised when I do something because that is what I believe in.
"When they do really believe, they will surprise themselves. And it's the best feeling ever."
Cahill believes his biggest impact on Australian football is still 20 years away and only then, he says, will his legacy be known.
And it won't be the goals he's scored or the games he's won - it will be the fruits from his coaching academies.
"The last seven years I have been doing my own grassroots programs in Australia," he said.
"It's having a massive impact on everyday children because I know when you start funnelling upwards, I will affect the game in 20 years.
"My crop of boys or girls that come through will be the future of football.
"Whereas when you start at the top and have the end product and filter the way down, then you're only filling up cracks that have been there forever.
"It definitely for me has always been about leaving a legacy. It has always been about affecting the game."
