He trialled with fellow graduate Caleb Rufer at German clubs Werder Bremen, Hannover and Borussia Mönchengladbach.

Neither player was successful, but Rojas was awarded a trial with the Wellington Phoenix after winning the Retro Ricki Youth Scholarship from the supporters group Yellow Fever.

Rojas impressed Wellington coach Ricki Herbert and put in some good performances in the Phoenix's warm up friendlies, resulting in him getting offered a 2-year contract with the A-League side.

Rojas provided the assist for Chris Greenacre's opening goal in a 3–1 win over North Queensland Fury in the Phoenix's final home game of the 2010–11 season.

[11] It was believed at the time that Melbourne Victory, Adelaide United and a South American club were vying for the signature of the highly rated youngster.

[12][13] On 11 March 2011, Melbourne Victory ended weeks of speculation by officially confirming that they had indeed signed Rojas, securing him on a two-year deal.

[23] On 10 July 2013, Marco started his first game for Die Schwaben in a pre-season friendly match against the local Hohenlohe-Selection at the Schönebürgstadion, Crailsheim.

In July 2022, Rojas moved to Chile, the native country of his father, and joined Colo-Colo on a deal for eighteen months.

[36] On 8 March 2011, Rojas was called up for the 30-man squad for the upcoming games against China and Japan for New Zealand's national team the All Whites.

Australia won the game 5–0 Rojas was selected for the New Zealand U-20 team to compete in the 2011 OFC U-20 Championship in April 2011 and the Suwon Cup in Korea.

During the OFC U-20 championship he played in all four matches helping the Junior All Whites win the tournament and secure qualification to the 2011 FIFA U-20 World Cup.