"[11] Many spectators hailed him as Brazilian and Real Madrid great Roberto Carlos' potential successor in the left-back role.

[12] On 14 April 2007, then coach Fabio Capello gave Marcelo his first start for Real Madrid against Racing de Santander.

After a string of poor performances in 2009, Marcelo found himself on the bench for much of the remaining season while under new manager Juande Ramos, mainly as deputy to the more defensive-minded Gabriel Heinze.

He scored his first goal after receiving a heel flick from striker Gonzalo Higuaín and slotting the ball past the goalkeeper in Madrid's 4–0 thumping of Sporting Gijón.

After the game, coach Ramos declared that Marcelo's future would be positioned as a winger, but will push back to defense when required.

Marcelo scored his second goal for Real Madrid in a victory over Almería, a powerful strike from outside the box with his weaker right foot.

Under the next head coach Manuel Pellegrini, Marcelo consistently featured in the starting XI for his versatility and pace along the left flank in offensive and defensive roles.

He continued to be employed as a left-winger under Pellegrini, and reached the top of the assist charts of La Liga in the 2009–10 season.

"[15] His successful performance in Real Madrid's 2009–10 campaign earned him a contract extension on 5 February 2010 with the club until June 2015.

Paolo Maldini gave credits to Marcelo and called him the current left back, "who is a great attacker and a defender, a specialist of both areas.

[21] Marcelo had shown great performances as a left back, such as in the Champions League quarter-finals against Cypriot club APOEL, while entering as a substitute in the 75th minute for Fábio Coentrão.

In the 14th minute, he sustained a muscle injury after intercepting a long through-ball, but the game ended in 3–1 victory for the home side.

[36] On 30 April 2022, after winning La Liga, Marcelo became the player with most titles in the history of Real Madrid, surpassing Paco Gento, with 24.

[37] On 28 May 2022, Marcelo lifted his fifth Champions League trophy after defeating Liverpool 1–0 in the final at the Stade de France, despite not featuring in the game itself.

[45] Four days later, Marcelo scored his first goal in his second tenure at the club with a long-range strike in a 4–1 victory against Flamengo in the second leg of the Campeonato Carioca final.

[49] Marcelo scored in his Brazil debut on 5 September 2006, in a 2–0 victory against Wales at Tottenham Hotspur's White Hart Lane.

Marcelo has been compared to former Brazil national team left-back Roberto Carlos, who also played for Real Madrid.

He was the Man of the Match for a 2–1 win in a friendly against Mexico away on 11 October 2011, as he scored the winner by dribbling past several players and then blasting the goal into the net.

[9] Marcelo was selected to be in Luiz Felipe Scolari's 23-man Brazil squad that played in the 2013 FIFA Confederations Cup on home soil.

[53] In the 2014 FIFA World Cup, which was once again played on home soil, Marcelo scored an own goal in the 11th minute of the opening game against Croatia on 12 June, deflecting a shot by Nikica Jelavić.

[56] Marcelo was praised by football legends such as Paolo Maldini[20] and Diego Maradona,[19] the latter of whom also called him the best left-back in the world.

[60][61][4][62] His movement on the ball, explosive pace, agility, and dribbling skills frequently see him beat opponents in one-on-one situations with feints.

He is a threat on counter-attacks, as he can penetrate the opponent’s defense with deep runs or get into positions where he can receive the ball often and create goals.

Moreover, his crossing ability, precise passing, and his vision also allow him to function as a secondary playmaker for his team, as he can create goalscoring chances for his teammates.

[77][78][79] In April 2013, Marcelo was unveiled as one of Adidas' new icons for a promotional event at the Bernabéu store which showcased the F50 adiZero.

Marcelo was joined by Real Madrid teammates Gareth Bale and Karim Benzema, who also wore the Adidas brand.