Vietoris started his career through karting, the most common entry point for all racing drivers, in 1994. Nine years after starting his karting career, the young German was the national Junior Kart champion and a year later came second Western German Karting Championship.
In 2005, Vietoris moved up to Formula BMW ADAC with Eifelland Racing. Vietoris finished his first FBMW campaign sixteenth in the Drivers' Championship with fifteen points, sharing his position with fellow German Dominik Wasem. In 2006, Vietoris moved to Josef Kaufmann Racing, where he won the Drivers' Championship with 277 points and taking nine race wins, his nearest rival being Finland's Mika Mäki. As well as his German FBMW title, Vietoris won the Formula BMW World Final, ahead of other FBMW champions such as Robert Wickens, the 2006 US FBMW champion, and the British Formula BMW champion, Niall Breen, winning himself a test for the BMW Sauber F1 team.
He continued in the F3 Euroseries in 2009 with Mücke Motorsport, finishing as runner-up to the dominant Jules Bianchi. Vietoris won four races over the course of the season, adding a further four podiums and a fastest lap at Brands once again, as he helped keep Mücke in contention for the teams title until he left for GP2 Asia.
Vietoris remains with Racing Engineering for the 2011 GP2 Series season, alongside Dani Clos. After crashing heavily during the first round of the season at Istanbul, he complained of recurring headaches and was replaced by Álvaro Parente until he recovered and returned to the cockpit in Valencia.[2] At Spa-Francorchamps, he took his first series pole position and converted it into victory, also setting his first fastest lap in the process. He also won the sprint race finale at Monza, rising to seventh in the drivers' championship.
DTM
Vietoris made his debut in the DTM, dovetailing his 2011 GP2 campaign with a season driving a Persson MotorsportMercedes in the Deutsche Tourenwagen Masters. His best result as a rookie was a 5th place at Oschersleben. Another highlight was reaching the semi-final at the non-points Showevent at the Olympic Stadium in München.[citation needed]
7-time F1 World Champion Michael Schumacher was to be involved with the three drivers by serving as a mentor. Driving under the Junior Team-moniker meant for Vietoris that he would switch teams for his sophomore season in the DTM, trading in his place at Persson Motorsport for the elite team of Mercedes in the DTM, HWA Team, replacing Bruno Spengler, who left Mercedes for BMW.[3]