Height: 6 ft. 2 in
Weight: 165 lbs
Turned Pro: 2000
Birthplace: Mettman, Germany
Siem turned pro at the age of 20 years old in 2000. After attending European Tour Q School in 2001, Siem captured his first ever main Tour card for the following season. He had a poor rookie season where he made the cut 7 times in 17 events. He managed two top 10s but still finished the year 131st on the money list and therefore, had to return to Q School to regain his card.
Siem shot a final round of 66 to claim his first European Tour win at the 2004 Dunhill Championship. He defeated Frenchmen Gregory Havret and Raphael Jacquelin after three play-off holes. Siem would have a further four top 10s to end the season 39th in the standings. In 2006, he partnered Bernhard Langer at the World Cup where they won the event for Germany. He would have to wait eight years to capture his second Tour title. In 2012, he closed with a 67 to win by one stroke from Italian Francesco Molinari at the Alstom Open de France. He also had a runner-up finish that year at the Avantha Masters and finished 14th on the money list.
Siem would win again the following season, this time at the Trophée Hassan II where he won by three strokes, largely helped by an opening round of 64. He had his fourth and biggest win to date in 2014 at the BMW Masters. He beat Ross Fisher and Alexander Levy after a play-off to claim victory. The event is part of the Race to Dubai play-offs. His best finish to date in a Major Championship was a tie for 12th place at the 2014 US Open. He ended the year a career high 7th on the European Tour money list.