He can count Spain legend and FIFA World Cup winner Andres Iniesta and fellow ex-Barcelona man Bojan Krkic as his current teammates, and has also shared a dressing room with famous names such as David Villa, Lukas Podolski and Thomas Vermaelen in recent times.
Just two years back, he helped Vissel win the first silverware in the club's history in the form of Japan's Emperor's Cup -- a tournament that has been in existence for over a century.
Yet, it was not too long ago that Osaki was playing in the less-illustrious setting of the now-defunct North American Soccer League for the Carolina RailHawks (now USL League One outfit North Carolina FC).
While most aspiring Japanese footballers usually make their way through the youth and reserve ranks of J.League sides or sign for clubs directly after starring for university teams, Osaki's unique journey saw him begin his professional career in the United States -- where he spent time as a child.
It was a move borne out of necessity but one that gives an insight into Osaki's sheer desire to make a career out of football and willingness to take any path necessary for it to happen.
"After I graduated from university, I didn't have any offers in Japan," Osaki told ESPN matter-of-factly.
"That's where I started to look for tryouts overseas and, since I grew up in the States, I was really interested in playing in the MLS and NASL.
"I just found a tryout online, signed up for it and went for it."
His days in Carolina may be a far cry from what he is currently accustomed to, with that 2019 Emperor's Cup final that Vissel won having been played in front of 57,597.
In the most recent season before the coronavirus pandemic, Vissel's Noevir Stadium Kobe averaged over 21,000 spectators a game.
Still, Osaki looks fondly back on his time with the RailHawks not only as having been the foundation for all he has gone on to achieve since but also imbuing in him a resilience he still draws on till today.
"Definitely, playing two years in the States gave me confidence. Playing against stronger opponents -- mentally, physically -- I think it grew my game a lot", the 30-year-old explained.
"After two years, I grew my confidence and that's where I thought I wanted to take another shot in the J.League.
"Playing in the States, I was able to speak the language so I didn't suffer a lot but still, playing in another country where you don't have friends was a little bit tough, and I think that's where my mentality grew.
"It's been six, seven years since I've been back in Japan but when I face other tough situations, I just think that the tougher situation for me was playing in the NASL. My first two years in the States is just everything for me right now."
Osaki's story is certainly one of self-belief and hard work, and he believes it was both of those -- "half and half" -- that has brought him this far.
At present, Osaki find himself in the curious situation playing for a star-studded team who look like they could be genuine contenders to become continental champions this season -- with Vissel through to the ACL Round of 16 with a game to spare -- yet struggling on the domestic front having gone the first ten games of the 2022 J1 League season without a win.
Having previously had a taste of plying his trade abroad, albeit out of necessity back then, Osaki -- who is equally comfortable playing in both defence and midfield -- is not ruling out another overseas sojourn now that he is an established professional, although his immediate target remains success with Vissel.
"I'm always interested in playing abroad. Because I can speak English, I think I would be able to establish myself a lot faster than other players that can't speak the language," he added.
"But for me, right now, the focus is on my team, to win as many titles as we can, and I think the opportunities will come after that."
And with his quiet confidence but also an appetite for working hard, it will certainly be captivating to see where his enthralling journey -- which intriguingly began in Carolina before heading back to Japan and is now making its way across Asia -- will take Osaki next.