In 2000 Vernay started his karting career . 2005 he played in the French Formula Campus his first season in single-seater racing and was champion of the series. In 2006 the young Frenchman switched to the French Formula Renault and secured the runner-up title. He also took part in two races of the Formula Renault 2.0 Eurocup. In the A1GP season 2006/2007 he took part in a few races for France. In 2007 Vernay switched to the Formula 3 Euro Series and finished ninth in the overall standings for Signature Plus . Vernay was also active in the Formula 3 Euro Series the following season and improved to eighth place overall. In 2009 Vernay stayed with Signature-Plus and contested his third season in the Formula 3 Euro Series. After not winning a race in the past two years, he celebrated two wins this season. At the end of the season he finished fifth overall.
For the 2010 season, Vernay switched to Indy Lights to Sam Schmidt Motorsports . He immediately succeeded in winning the season opener in St. Petersburg . In the second race in Birmingham he managed to achieve pole position and the fastest lap and lead the race for the most laps. He succeeded in this combination again during the season. Vernay scored a total of five wins in the 2010 season, all of them on circuits. On the oval courses, two third places were his best results. Eventually he won the championship ahead of James Hinchcliffe . In 2011 Vernay couldn't find a cockpit for a full season. He took part in the second Formula Renault 3.5 race weekend for Pons Racing . He also made his debut in the American Le Mans Series (ALMS) and competed in an LMP2 car. After the season he also did test drives in the DTM for BMW .