After he had been active for several years in karting, he gave in 2005 his debut in Formula racing. He started both in the Belgian Formula Renault 1.6, in which he finished third overall, and in the Italian Formula Junior in 1600, in which he won the runner-up title behind Pasquale di Sabatino. In addition, he participated in four races of the Formula Renault 2.0 Euro Cups in part. After the season, he took part in the Winter Series of the Italian Formula Renault and finished ninth. 2006 denied Marinescu once again the complete season two racing series. He was sixth in the Northern Europe and eleventh of the Italian Formula Renault. He also appeared in three races in the French Formula Renault. 2007, Marinescu improved to fifth place in the Italian Formula Renault and eleventh in the Formula Renault 2.0 Eurocup was beyond. He also participated in two races in the British Formula 3 Championship (National as a guest ) and the FIA GT3 European part.
In 2008, the main focus of Marinescu was on the European Formula BMW, in which he finished in eleventh place in the championship at the end of the season. In addition, he competed in races of the Formula BMW Pacific American and as a guest as well as in the International Formula Master. 2009 Marinescu received no cockpit for an entire season and started for two teams in 11 of the 17 races of the 2009 season of Formula Renault 3.5. He scored no points and finished the season 30th overall.
2010 moved Marinescu in the FIA Formula 2 Championship and finished the season in eleventh place overall. In 2011 he completed his second Formula 2 season. With a win, he finished the season from fifth place in the overall standings. After the season, he took part for the Rapax GP2 Final in 2011 and was denied Marinescu 24, 2012 his third Formula 2 season. He won two races and reached once again ranked fifth in the drivers' standings.
2013 Marinescu returned back into the Formula Renault 3.5. He received a cockpit in the new team Zeta Corse. After he had paused at the third race weekend, he lost his cockpit final after the fifth race weekend. An eighth place was his best result. He was 25th in the overall standings. In addition, he completed two guest appearances in the Eurocup Mégane Trophy, a touring car series.
- 2005: Italian Formula Junior ( 2nd place)
- 2005: Belgian Formula Renault 1.6 ( 3rd place)
- 2005: Formula Renault 2.0 Eurocup ( No. 47 )
- 2005: Italian Formula Renault Winter Series (No. 9)
- 2006: North European Formula Renault ( 6th place)
- 2006: Italian Formula Renault (11th )
- 2006: French Formula Renault
- 2007: Italian Formula Renault ( 5th place)
- 2007: Formula Renault 2.0 Eurocup (11th )
- 2007 FIA GT3 European Championship
- 2008: European Formula BMW (11th )
- 2008: International Formula Master (rank 22)
- 2009: Formula Renault 3.5 (ranked 30)
- 2010: Formula 2 ( # 11 )
- 2011: Formula 2 ( 5th place)
- 2012: Formula 2 ( 5th place)
- 2013: Formula Renault 3.5 (ranked 25)