He spent much of his early career in karting before moving into single-seaters in 2004, where he competed in both Brazilian Formula Renault and the South American Formula Three championship.
In 2005 he contested six races in the Spanish Formula Three Championship, finishing the season 20th overall. Carlos also contested a handful of races in Italian Formula Renault and the Eurocup Formula Renault series as well as making his debut in the Formula Renault 3.5 Series for the Austrian team Interwetten.com.
For 2006 Iaconelli raced in the Formula Renault 3.5 Series for three different teams – Eurointernational, Comtec Racing and GD Racing, taking part in twelve races. He also contested five races in the Spanish Formula Three Championship.
For the 2007 season he originally joined Pons Racing.
In 2008 he raced in the International Formula Master series. He also made his GP2 Series début mid-season, driving for the BCN Competicion team. He moved to the Durango team for the 2008–09 GP2 Asia Series season, but was replaced by Michael Dalle Stelle following the first round of the championship.
2009 saw Iaconelli move to the FIA Formula Two Championship, driving car number seventeen. Despite missing the final round at Circuit de Catalunya due to flu, Iaconelli wrapped up eleventh place in the standings, with his best result of second also coming in Spain, in Valencia.
In 2011, Iaconelli raced in NASCAR for the first time. He completed a test with X Team Racing in Hickory Speedway and another one in Motor Mile in Virginia.
He debuted in November 2011 at the 1 mile oval in Phoenix International Raceway finishing a very impressive 12th on his first NASCAR race in the NASCAR K&N Pro Series East.
For 2012 he will race full time with X Team Racing and will driver the # 15 Toyota Camry.
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