Mancienne was a prodigious talent who emerged from Chelsea's academy in 2006, winning the club's Young Player of the Year award and a FA Cup winners medal in 2009.
That's when the versatile defender made the unorthodox decision to join Hamburg, making him the only English player in the Bundesliga.
Upon reflection, Mancienne told Tribalfootball that the move was inspired partly because of his experiences in the Chelsea dressing room.
"And I thought why don't more people, and I know the Premier League is one of the best in the world, but I just always felt I'd want to play abroad.
"It just always kind of stuck with me and then when the opportunity came along, I thought wow, why not just take it, it might not come around again, football's a short career so you've got to make the most of it so I took that opportunity, and I loved it.
"It was one of my favourite times in my career to be honest."
Mancienne would return to England with Nottingham Forest in 2014 after 55 appearances in three seasons for Hamburg.
But the influence of Mancienne's spell would continue, as a number of young players - Jadon Sancho and Ademola Lookman to name a few - have made the switch to Germany after finding opportunities limited in the Premier League.
As a trailblazer for the current generation, Mancienne is happy to see people embracing the Bundesliga.
"I'm buzzing for them and that they're doing well. It's a great move, especially when they are playing in big teams so it's great, they're making a name for themselves you get a different experience of football.
"That time when I was there as well, Germany as a national team were unbelievable and you had teams like Bayern Munich who should've been in a seperate league, they should've been in the Premier League, because nobody could beat them in the league, they were ridiculous.
"So it was just a great experience to play against them and world-class players."
Borussia Dortmund winger Sancho has been linked with a return to England, with Manchester United and Liverpool reportedly interested.
And Mancienne thinks the 19-year-old should not rush his decision.
"He just needs to do what makes him happy to be honest. I don't think there's a massive rush to come back to England.
"It's not like Bundesliga is a terrible league, it's an unbelievable league. It's got great teams and every team tries to play football, there's not a team, even the ones towards the bottom, they're not playing long ball, they're actually trying to still play out from the back."