"At one stage, there was a chance I could have been involved with Scotland," he recalled. "I was given the offer and had a long, hard think about it.
"But I'd wanted to play for Australia ever since I was a kid. I'd represented my country at every level bar the full team at that time, and also captained the under-21s. There was no way I was going to turn my back on the chance of making the next step.
"Thankfully, I have now done that. Hopefully, there are many more caps for me to come and we can make the next World Cup. That's the main goal for myself and the rest of the up-and-coming Australian talent."
"At first, it was Berti Vogts who was interested," McDonald told The Herald. "Then my agent got a call when Walter Smith was in charge, I think to see if I could play in a B game.
By that time, I'd already made my choice. On both occasions, I just politely declined.
"My parents are both Scottish, so I would have been more than qualified. But I was born in Australia and I feel Australian. That's my culture.
"My folks would have been proud either way. I'm sure my dad would have been happy if I played for Scotland but, all the same, they're thrilled I'm playing for Australia. That's the place my family live now."
"I'll definitely be a Scotland fan on Saturday," admitted McDonald. "I've a lot of good team-mates playing for them now, but even before I always followed them and wished them all the best . . . apart from when they played Australia.
"It's good to see Scottish football taking a massive turn for the better. It gives the league a higher and more positive profile."