Signed to a multi-year deal from Bundesliga outfit FC Nuremberg, 29 year-old Broich joins the Roar after being heavily pursued by coach Ange Postecoglou.
Recognising the former German under-21's signature as a critical acquisition for the upcoming campaign, Postecoglou believes the chase was well worth the effort.
"I went to Europe looking for a player who can play an attacking midfielder but can also contend with the physical demands of the league," Postecoglou said.
"I went with the intention of signing Thomas ... but it was a bit of a challenge as he's still only 29 and can probably get another Bundesliga club quite easily.
"It took four or five weeks of negations but in the end we were able to get him and I was delighted because I think he is exactly the player we need.
"I'm sure he will make a major impact in the Hyundai A-league ... and he is definitely one of our key signing for the year."
Skilful, technical and experienced in the art of European football, Broich travels to Brisbane after spending nearly a decade in German football.
Enjoying stints at top flight clubs FC Nuremberg, Borussia Monchengladbach and FC Koln, Broich's name stood out amongst the long list of potential signings.
"You get nearly a hundred recommendations a day and when I went to Europe I saw quite a few players and made all the enquiries," he said.
"But with Thomas, everywhere I looked and people I asked, it was a pretty consistent message that he's a very good player and will do very well in the Hyundai A-league."
"I did as many checks as I can, but at the end of it he ticked all of the boxes in terms of what I'm looking for and what I think the team needs."