But aside from living every footballer's dream of winning the competition with his boyhood club, the Brazilian is now part of an exclusive club featuring former stars of Barcelona, AC Milan and even Leeds United.
Fluminense came from behind to clinch a 2-1 win in extra time in a dramatic final against Argentina's Boca Juniors, who had ex-Manchester United striker Edison Cavani score.
The chaotic game saw two red cards dished out, with one going to John Kennedy, the man who scored Fluminense's winner.
That didn't stop the Brazilian side seeing out the match and winning the competition for the first time in their history.
Unsurprisingly, Marcelo was left in tears as realised his dream of becoming a champion of South America with the club he started playing for as a youngster in 2002.
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The achievement is even more incredible considering he only just returned to his boyhood club in February after a spell with OIympiakos after leaving Real Madrid.
This weekend's trophy win is the 26th major title of Marcelo's illustrious career.
He's now also become the fourteenth player in football history Barcelona to win both the Champions League and the Copa Libertadores, with Marcelo winning the European competition five times with Los Blancos.
Barcelona legends Neymar, Ronaldinho and even former Leeds star Roque Junior are among those to have achieved the feat.
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When asked by ESPN whether this weekend's achievement or the Champions League wins with Real Madrid meant more, an emotional Marcelo said: "Real Madrid will understand. It's my most important title, at club level, because it's the club that raised me.
"I'm winning a very important title with my favourite club, the club that gave me all the tools to have my career, with the employees who saw me grow up. There's nothing more rewarding than that. It's priceless.
"I owed a debt to Fluminense. It was written."