The 27-year-old came through the Roar system where he made his A-League Men debut in 2015 before stints under Socceroos coach Popovic at Perth Glory and Melbourne Victory.
D'Agostino, who made his Socceroos debut in 2022 in a World Cup qualifier against Saudi Arabia, is on loan from Norwegian first division champions Viking FK for the rest of the ALM season.
Making the 2026 World Cup squad and inspiring a Roar finals fairytale are his aims.
"The goal is to come here and get consistent minutes, score some goals and go to the World Cup," D'Agostino told AAP.
"The focus is on Brisbane now, day-in and day out, and to make sure the body feels good and I can have as big an impact as possible. Obviously we want to push for that finals spot and create something special."
Popovic has been a guiding force in D'Agostino's career and was a sounding board before he made the move.
"It obviously played a massive part," he said.
"He gave me his blessing to come back to the A-League and to Brisbane as well, specifically.
"I have been in constant communication with him and all the national team staff. Brisbane felt like the right fit for me.
"(Popovic) is very detail orientated about every specific thing, whether that is on the field or off the field in terms of recovery and nutrition. It's just about maximising yourself to the best of your ability in every aspect of your life. He's been very instrumental in my career."
D'Agostino has admired the steel Roar coach Michael Valkanis has put in the fourth-placed side and one meeting was enough to reinforce that view.
"I had a meeting with him a few weeks back to see what his thoughts were about me coming back to Brisbane," D'Agostino said.
"It was a great chat and I had a very positive feeling after about his ideas and what he wants to see in future at the club. I am looking forward to working with him and hopefully we can create some special memories together.
"They have got a good defensive record but I am here to score goals and win games. I know my quality and I have belief in myself that I can come here and do that ... and obviously they do as well."
D'Agostino said it was still a "wait and see" scenario as to whether he would play in Saturday night's home clash with Adelaide United, but admitted to feeling "very nostalgic" to be back in Roar colours.
"I had John Aloisi as my coach (in 2015) who gave me my debut. There were some great times and a lot of memories and players I still keep in contact with," he said.
"It's great to be back.This is home for me. I spent my first week getting to know everyone and getting that camaraderie so we can gel, but once we get going it should be fun to watch.
"I will keep working with the staff and make sure the body is good to go. I only had my first session today and everything felt good."
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