Leckie has never played under coach Tony Popovic due to recurring soft-tissue injuries.
But he returned for Melbourne City at the back end of the season before earning a call-up to the training camp after a mammoth 120-minute elimination final midfield shift against Auckland.
Leckie has been in the thick of Australia's gruelling pre-World Cup training camp, which the 35-year-old described as a "mini pre-season" in hot and humid Sarasota.
"It's been very different to what I was used to, obviously, it almost felt like it was my first time into camp again," Leckie said on Friday.
"A lot's changed, obviously, a lot of the coaching staff and some staff as well, and not just that, a lot of fresh faces and young players.
"So I was super excited, and it's been really good - there's a high expectation, a high demand, it's a very professional environment, so it's been exciting."
Qatar 2022 hero Leckie last played for Australia against Palestine back in June 2024 amid a torrid injury run that forced him to pull out of multiple camps, while he also missed the 2024 Asian Cup.
Leckie had hip surgery in December in a bid to get to the bottom of, and hopefully bring an end to, repeated hamstring and calf strains.
"Obviously it's been a frustrating time ... but I guess I've just always had the mentality that I could get back," the Melburnian said.
"And I feel obviously without injury when I'm out there, I'm still capable to be in good shape.
"I don't feel like I'm slowing down in any way, and the key has been to try to stay fit.
"If I was not, I guess the player I have been, it would be different, but I still think I've still got a lot to give when I'm fit."
Popovic clearly sees that too, having been effusive in his praise of Leckie's powerhouse display against Auckland, which the versatile veteran believes set him up to perform in camp.
"I'm very fortunate to be here after, the injuries that I've had - I guess lucky in a way to be back at this time and not be injured in this period, but also that I've even been given the opportunity to be here," Leckie said.
"So I've really put my head down in this camp and tried to work hard and do everything right to give myself a chance."
Leckie made his name as an explosive attacker but has spent more time in midfield at City and has trained in different positions in Socceroos camp.
"I'll put my hand up to help any way the boss thinks I can," he said.
The veteran has enjoyed getting to grip with a new system and is excited to see what young talents, headlined by Nestory Irankunda and Mohamed Toure, can do.
"Obviously both very exciting players. We've seen that in the national team, but also back at their clubs," Leckie said.
"They're doing great things, and they're players that can make something happen out of nothing, and they're in a really good position to have a really bright future.
"The World Cup is something special, and it's a place where, if you can at a young age do something in front of the world, can take you to big places."
