Trummer began his motorsport career in 1999 in karting, where he was active until 2007. Among other things, was vice-champion in 2003 the Swiss Junior Kart Championship. After he had in Formula Lista Junior made his first experience in Formula racing in 2006 and finished the season in 18th place, he went in 2007 in the Swiss Formula Renault at the start, finishing in seventh place overall. 2008 Trummer remained in the Swiss Formula Renault. He won two races and was runner-up behind Christopher Zanella. He also competed in six races of the Italian Formula Renault.
After the Swiss in two races in the International Formula Master for the Iris Project was started in 2008, he was awarded with the team signed a contract for the 2009 season. With a third place as best result he finished at the end of the season 11th in the championship. 2010 Trummer went for Jenzer Motorsport in the new GP3 Series at the start. After an accident at Hockenheim, in which he drew upon a back injury with a broken and three fractured vertebrae, he had to pause a race weekend. In contrast to his team-mate Nico Müller and Pål Varhaug Trummer did not win a race and scored only two points race. At the end of the season, he finished 25th overall. 2011 remained Trummer in the GP3 Series and went for MW Arden at the start. While his team-mate Mitch Evans and Lewis Williamson each won a race was a fourth place his best finish. The championship he finished in 18th place. After the season, he took part for the Arden GP2 Final in 2011 and was 21
2012 Trummer went for Arden International in the GP2 series at the start. While his team-mate Luiz Razia was runner- Trummer reached the 23th place in the Drivers' Championship with a seventh place as best result. For the 2013 season changed Trummer within the GP2 Series to Rapax. At the season opener in Sepang Trummer scored his hitherto best GP2 result in both races and points with a sixth place in the sprint race. In the main race at the Hungaroring, he scored another sixth place. He finished the season at the 21st place overall with 20 points, while his teammate Stefano Coletti had reached 135 points for fifth place. 2014 graduated Trummer another GP2 season for Rapax. At the season opener in as- Sachir Trummer succeeded starting from the pit lane with a different strategy, seventh place. In the subsequent sprint races he scored with a second place finish his first podium placement in GP2. After the first race weekend, he finished fourth overall.
- 2008: Italian Formula Renault ( No. 33 )
- 2008: International Formula Master (rank 30)
- 2009: International Formula Master (11th )
- 2010: GP3 Series ( No. 25 )
- 2011: GP3 Series ( No. 18 )
- 2012: GP2 Series ( No. 23 )
- 2013: GP2 Series (No. 21)
- 2014: GP2 Series