Kolles grew up in Romania before settling in Ingolstadt, Germany, where he qualified as a dentist in the family tradition. His entry into motorsport came in 2000 when he co-founded a racing team with his father Romulus in the German Formula Three Championship; that team eventually became the Vanwall Racing Team. The dentistry qualification proved unexpectedly useful during his Formula One tenure: before the 2005 Turkish Grand Prix, Kolles performed emergency dental surgery on his driver Tiago Monteiro to keep him race-eligible, and repeated the feat on Christijan Albers at the 2006 French Grand Prix.
On 19 January 2005, Alex Shnaider — the new owner of the Jordan Grand Prix team — appointed Kolles as managing director. Although his blunt management style drew criticism that year, he retained the position through multiple ownership changes. He oversaw the launch of the Midland M16 chassis for the 2006 season and remained in post when Spyker purchased the outfit, and again when Vijay Mallya acquired it as Force India in 2008.
In November 2008, Mallya assumed the team principal role himself, leaving Kolles without a senior position at Force India. Kolles remained under contract until 31 October 2009, when he resigned as a director.
He returned to the Formula One paddock with Hispania Racing F1 Team (HRT), one of the three new entries for the 2010 season, serving as team principal. HRT was consistently the slowest team on the grid and withdrew from Formula One at the end of 2012. Kolles also worked as an advisor to the Caterham F1 project and was involved in the unsuccessful Forza Rossa Racing effort.
Between his Formula One stints, Kolles managed sportscar activities through Kodewa. In 2009 he fielded a pair of ex-works Audi R10 LMP1 prototypes in the Le Mans Series and at the 24 Hours of Le Mans, with a roster that included Michael Krumm, Charles Zwolsman Jr, Andrew Meyrick, Christian Bakkerud, Christijan Albers, and Narain Karthikeyan. He departed Kodewa in December 2011.
In July 2013, reports emerged that Kolles had attempted to blackmail Mercedes-Benz Motorsport director Toto Wolff after allegedly recording Wolff making negative remarks about the Mercedes F1 Team's management. The two parties settled the matter privately.
Kolles's career illustrates the precarious economics of the lower half of the Formula One grid: every team he managed was a midfield-to-backmarker operation changing hands under financial pressure. His longevity across multiple rebrands — Jordan to Midland to Spyker to Force India — made him one of the more durable administrators in an era of rapid ownership churn among smaller outfits.