Yet the South Korean international appeared remarkably carefree in the club's packed media room, despite countless journalists from all corners of the globe - especially the far-east - eager for details of his move.
"Show what I can do"
"A lot of clubs enquired about me," said the recently-turned 21-year-old. "I spoke to some of them, but I'm very happy to be here. It was important for me to play international football this season. We want to qualify for the Champions League again next term and play good football - we'll give everything to make that happen."
While a full international with his country already, Son is yet to taste life in a European club competition, having broken through too late to partake in Hamburger SV's last shoulder-rubbing session with the continental elite. However, he appears well-equipped to cope with the added demands: "I know a lot of money's been spent on me and of course the pressure is bigger because of that. I need to show what I can do out on the pitch and try to help the team."
Having found the net 12 times in the Bundesliga last season, that will be music to Leverkusen fans' ears, especially considering the potential strike partnership Son could form with 2012/13 top scorer Stefan Kießling.
The thought had evidently crossed Son's mind too: "For me it's a dream to play with . There's so much I can learn from him. I'm one of the new boys here and we all want to prove our worth."
Big boots to fill
As only the second South Korean to lace up his boots for Leverkusen, questions were inevitably asked about Son's trail-blazing compatriot Bum-Kun Cha, who was at the club in the 1980s.
"He's a legend both in Korea and in Germany so it's a dream for me to be here," Son said. "When I was in Korea I spoke to Bum-Kun Cha. He gave me a few tips and told me 'you'll be fine'." All the evidence so far indicates he was right.